Basic Calculator

A fast, free calculator for everyday arithmetic. Tap the keypad or type on your keyboard — add, subtract, multiply, divide, and take percentages, chain operations together, and review every calculation in the history below. Click any history entry to bring its answer back.

How a Basic Calculator Works

Every calculation follows the same pattern: enter a number, choose an operation, enter the next number, and press equals. Chained operations work the way most pocket calculators do — each new operator first finishes the pending operation, so 2 + 3 × 4 evaluated left to right gives 20, not 14. That is different from strict mathematical order of operations, where multiplication comes first. If you need proper precedence with brackets and powers, use the scientific calculator, which follows BODMAS/PEMDAS exactly.

The four operations are the foundation of all arithmetic. Addition combines quantities, subtraction finds differences, multiplication is repeated addition, and division splits a quantity into equal parts. Percentages are a shortcut for division by 100: pressing % turns 50 into 0.5, which is why "20% of 80" can be worked out as 80 × 20% = 16. The percentage calculator covers every percentage question in depth.

Order of Operations, Honestly Explained

School maths says: brackets first, then powers, then multiplication and division (left to right), then addition and subtraction (left to right). So 2 + 3 × 4 = 14, because 3 × 4 happens before the addition. But a basic calculator with chained entry computes as you go: 2 + 3 = 5, then 5 × 4 = 20. Neither is "wrong" — they are different input styles. The confusion causes real errors, so always know which style your tool uses. This calculator shows the running trail above the display so you can see exactly what it did.

For averages of lists, see the average calculator; for roots, the square root calculator; and for fractions, the fraction calculator. The Khan Academy arithmetic courses explain these foundations with practice exercises, and Wolfram MathWorld documents the formal rules.

Tips for Accurate Everyday Maths

• Estimate first. Before trusting a long calculation, round the numbers and check the ballpark — it catches misplaced decimals instantly.
• Watch the decimal point. A single slipped decimal multiplies an answer by ten. The display shows commas for thousands to help you read large results.
• Use history. Every result above stays clickable, so multi-step problems (like splitting a bill, then adding a tip) never lose an intermediate answer.
• Percent means ÷ 100. To find 15% of 60, type 60 × 15 % = and read 9 — the % key does the division for you.
• Division by zero is undefined. No number divided by zero has an answer, so the calculator refuses it rather than inventing one.

Mental Maths Shortcuts

A calculator is fastest, but a few mental tricks make you faster still — and they double as error checks on anything the calculator says. To multiply by 11, take a two-digit number like 34, add its digits (3 + 4 = 7), and put the sum between them: 374. If the sum is 10 or more, carry: 48 × 11 = 528, because 4 + 8 = 12, so the 1 carries to the 4. To multiply by 5, halve the number and multiply by 10: 86 × 5 = 43 × 10 = 430. To multiply by 25, divide by 4 and multiply by 100: 72 × 25 = 18 × 100 = 1800.

Subtraction has a friendlier trick too: instead of 1000 − 647, add up from 647 to 1000 — 3 gets you to 650, 50 to 700, 300 to 1000, for a total of 353. Shopkeepers have used this "counting up" method for centuries because it avoids borrowing entirely. And for percentages, remember that 10% is one decimal shift, 1% is two shifts, and everything else is built from those: 13% of 250 is 25 + 2.5 + 2.5 + 2.5 = 32.5. These shortcuts will not replace a calculator for long problems, but they make estimation instant — and an estimate that disagrees with a calculator answer is the fastest way to catch a typo before it matters.

Everyday Calculations: What to Type

Most daily arithmetic is one of a handful of patterns. The table below shows each pattern with the exact keys to press on this calculator, so you can go from a real situation to an answer without stopping to think about method.

Two of these deserve a second look. The tip calculation works because the % key divides by 100: 60 × 15 % first turns 15 into 0.15, then multiplies, giving 9. And the discount row is a two-step job — find the discount first, then subtract it — because a basic calculator has no "take 25% off" button. For discounts with tax or stacked offers, the discount calculator does the whole chain in one place, and the percentage calculator covers every percentage question in depth.

Using History for Multi-Step Problems

Real problems rarely end at one equals sign. Suppose four friends share a $96 dinner and want to add a 20% tip before splitting. The clean way is in stages, using the history as a notebook. First, 96 × 20 % = gives the tip, $19.20. Click that history entry to load 19.20 back into the display, then add it: 19.20 + 96 = gives $115.20. Click the new history entry, then divide: 115.20 ÷ 4 = gives $28.80 per person. No intermediate answer was retyped, so no rounding crept in and no digit was mistyped.

The same trick rescues long shopping lists. Add each price as you go, and if you lose track, the history shows every step in order, newest first. If a step looks wrong — a price typed as 45 instead of 54, say — you can see exactly where it happened instead of starting over. One habit makes this reliable: glance at the trail above the display before pressing equals. The trail shows the pending operation and the running total, so a wrong operator pressed one step ago is visible before it corrupts the answer.

Keyboard Power Tips

The keypad is friendly, but the keyboard is faster for anything longer than two steps. Digits and the decimal point type directly, + − * / choose the operation, Enter is equals, Backspace deletes the last digit, and Escape clears everything. Because this calculator evaluates chained entry, typing 100 − 20 + 30 works left to right: 100 − 20 = 80, then 80 + 30 = 110. That matches a pocket calculator, but it is not BODMAS — for expressions where multiplication must come first, use the scientific calculator instead.

Two more keyboard habits pay off. First, after an equals, the answer stays in the display, so typing a new operator immediately continues from it: 12 + 8 = then × 3 = gives 60. Second, the ± key flips the sign of the current entry, which is the quickest way to subtract a number you just typed or to enter a negative value at the start of a calculation. Combined with the clickable history, these make the basic calculator fast enough for bookkeeping, till work, and homework checking without ever touching the mouse.

How to Use Each Operation

Every calculation on this page follows the same five steps, whether you tap the keypad or use your keyboard. Learning the steps once makes every later calculation faster, because you stop thinking about the buttons and start thinking only about the numbers in front of you. The display shows the number you are entering, and the small trail line above it shows the running total and the operation that is waiting. Read that trail before you press equals, especially in a longer chain, and most mistakes become visible while they are still easy to fix.

1. Enter the first number. Type the digits, using the decimal point key for a fraction of a whole number. Press the plus-minus key if the number should be negative.
2. Choose an operation. Press plus, minus, multiply, or divide. The first number moves into the running total shown in the trail.
3. Enter the second number. The display clears for the new entry. Check the digits before you go further, because a mistyped digit here changes everything that follows.
4. Continue the chain or finish. Pressing another operation finishes the pending step and starts the next one. Pressing equals finishes the whole calculation and shows the result.
5. Reuse or clear the result. After equals, the answer stays in the display, so a new operation continues from it. Press C to clear everything, or use Backspace to delete only the last digit of the number you are typing.

Addition: Combining Quantities

Addition answers the question "how much altogether?" Add shopping prices, add hours worked across a week, or add the parts of a bill. Type the first amount, press plus, type the second amount, and press equals. For example, 47 + 38 = 85, because 40 + 30 = 70 and 7 + 8 = 15, and 70 + 15 = 85. Money works the same way: 12.99 + 8.50 = 21.49. Addition is the safest operation to chain, because the order of the numbers does not change the total: 125 + 375 = 500, and 375 + 125 = 500 as well. When a total looks too small, the usual cause is a missed item rather than a wrong operation, so add the list again in a different order and compare the two totals.

Subtraction: Finding a Difference

Subtraction answers "how much is left?" or "how much more is needed?" Type the starting amount first, press minus, type the amount to take away, and press equals. For example, 500 − 137 = 363, and change from a $20 note for a $4.75 item is 20 − 4.75 = 15.25. Unlike addition, the order matters: 20 − 4.75 = 15.25, but 4.75 − 20 = −15.25, a negative result that means the second number is larger. Subtraction is also how you check an addition: if 47 + 38 = 85, then 85 − 38 must give 47 again. If it does not, one of the entries was typed wrong. Use subtraction for budgets, countdowns, weight change, price drops, and any "before and after" comparison.

Multiplication: Repeated Addition Done Quickly

Multiplication answers "how much for several equal groups?" If one ticket costs $14 and you buy 6, the total is 14 × 6 = 84, which is the same as adding 14 six times but far quicker. Other examples are 12 × 8 = 96, 7 × 6.5 = 45.5, and 25 × 4 = 100. Multiplication is useful far beyond the times table: area is length multiplied by width, a weekly wage is an hourly rate multiplied by hours, and a total for identical items is a unit price multiplied by quantity. The order does not change the answer, so 6 × 14 = 84 as well. When the numbers are large, estimate first — 14 × 6 is close to 15 × 6 = 90 — and a result far from the estimate is a warning to re-enter the numbers.

Division: Sharing and Comparing

Division answers "how much per share?" or "how many groups of this size fit?" Type the total first, press divide, type the number of shares or the size of each group, and press equals. For example, 144 ÷ 12 = 12, 75 ÷ 4 = 18.75, and 90 ÷ 6 = 15. Division is the operation behind unit prices, averages, hourly rates, and fair shares. The order matters a great deal: 20 ÷ 4 = 5, but 4 ÷ 20 = 0.2, which is a very different statement. Before dividing, ask which number is the total and which number is the divisor. If the answer should be smaller than the total and it comes out larger, the two numbers are almost certainly the wrong way round. Division results often need decimals, and that is covered in the decimals section below.

The Percent Key: Dividing by 100

The percent key has exactly one job: it divides the number currently on the display by 100. Pressing % after 50 gives 0.5, pressing % after 25 gives 0.25, and pressing % after 15 gives 0.15. That single behaviour is what makes percentage calculations short. To find 25% of 200, type 200 × 25 % = and read 50, because the calculator first turns 25 into 0.25 and then multiplies 200 × 0.25 = 50. To find 10% of 90, type 90 × 10 % = and read 9. The percent key does not add a percentage to a number, and it does not subtract one: 80 + 15 % gives 80.15, not 92, because 15 % is simply 0.15 added to 80. To add 15% to 80, first find the amount, 80 × 15 % = 12, then add it, 80 + 12 = 92. For discounts, tax, tips, and every other percentage question, the percentage calculator carries out the full chain in one place.

Chained-Entry Evaluation, Step by Step

This calculator evaluates a chain from left to right, finishing each step as soon as you press the next operation. That is the behaviour of most pocket calculators, and it is the behaviour this page describes throughout. Work through 2 + 3 × 4 exactly as the keys are pressed: 2 + 3 is finished first, giving 5, and then 5 × 4 gives 20. The trail above the display shows each running total as it happens, so the chain is never hidden. Strict school maths gives a different answer, 14, because it does multiplication before addition. Both answers are correct under their own rules, so the important skill is knowing which rule is in force before you trust a result. If an expression must follow strict precedence, work out the multiplication or division part separately first, or use the scientific calculator, which applies BODMAS and PEMDAS with brackets.

A second example shows why the order of key presses matters more than the order of symbols on paper. Take 100 − 20 + 30: the chain gives 100 − 20 = 80, then 80 + 30 = 110. Take 20 − 4 ÷ 2: the chain gives 20 − 4 = 16, then 16 ÷ 2 = 8, while strict maths gives 20 − 2 = 18. Neither result is a calculator fault. The calculator did exactly what the key presses asked, in the order they were pressed. The table below shows several chains side by side, with the strict result for comparison, so you can see at a glance which expressions give the same answer under both rules and which do not.

Notice that the last two rows agree under both rules. When only one kind of operation is involved, or when the operations happen to fall in the same order, chained entry and strict precedence give the same answer. The danger is only in mixed expressions where a multiplication or division appears after an addition or subtraction. A practical habit removes the risk: if an expression mixes addition or subtraction with multiplication or division, pause and decide which rule you need. For a running total, a till total, or a step-by-step problem, the chain is exactly right. For a written formula, a homework question, or a scientific expression, use strict precedence.

• Each new operation finishes the last one. Pressing × after 2 + 3 first computes 5, then waits for the next number.
• Equals finishes the chain. After equals, the answer stays on the display and a new operation continues from that answer.
• The trail is the truth. If the trail shows a different running total from the one you expected, stop before pressing equals and re-enter the chain.
• Brackets are not available here. There is no bracket key on a basic calculator, so a bracketed part must be worked out as a separate calculation first.
• Do the strong operation first when you need strict maths. For 2 + 3 × 4 under BODMAS, calculate 3 × 4 = 12 first, then 2 + 12 = 14.

Decimals and Division

Most everyday numbers are not whole numbers. Prices have cents, measurements have fractions of a unit, and division often leaves a remainder that must be shown as a decimal. This calculator handles decimals in the ordinary way: press the decimal point once, type the fractional digits, and the display keeps them exactly as entered. A result is shown rounded to 12 significant digits, as the disclaimer at the end of this page states, which is far more precision than shopping, cooking, or household budgeting ever needs. The display also adds commas to thousands, so 1234567 is shown as 1,234,567, which is easier to read and harder to misread by a factor of ten.

Working With Decimals

Enter a decimal by typing the whole part, the point, and then the fractional part: 4.75 is typed as 4, point, 7, 5. To enter a number smaller than one, start with 0, as in 0.5, which is the same as one half. Adding and subtracting decimals needs care only with place value: 9.99 + 0.01 = 10, and 12.5 + 3.75 = 16.25, because 12 + 3 = 15 and 0.5 + 0.75 = 1.25. Multiplying decimals is simpler than it looks: 7.5 × 4 = 30, 2.5 × 2.5 = 6.25, and 0.75 × 8 = 6. Dividing decimals follows the same rule as dividing whole numbers: 12.5 ÷ 2.5 = 5, because 2.5 fits into 12.5 exactly five times. If a decimal answer shows trailing zeros dropped, as 2.50 shown as 2.5, the value is unchanged — trailing zeros after the decimal point add no value.

• Press the point once. A second decimal point in the same number is ignored, so a number can never have two points.
• Line up the point when checking by hand. In addition and subtraction, the decimal points must sit in the same column, or cents will be added to dollars.
• Count decimal places for a rough check. Multiplying 2.5 by 4 cannot give 1, because 2 × 4 is already 8, so an answer near 1 means the point was misplaced.
• Expect long decimals from division. Dividing by 3, 6, or 7 usually gives a repeating decimal, and the 12-digit display is a rounded version of an answer that never ends.
• Round only at the end. Keep full precision through every intermediate step and round only the final answer, or small rounding differences will accumulate.

Dividing Fairly and Exactly

Division does not always come out even, and knowing what to do with the remainder is a practical skill. Sharing $10 between 3 people gives 10 ÷ 3 = 3.333333333333, which cannot be paid exactly in cents. In real life, two people receive $3.33 and one receives $3.34, which totals $10.00: 3.33 + 3.33 + 3.34 = 10. Sharing $10 between 4 people is exact: 10 ÷ 4 = 2.50 each. Sharing 7 pizzas between 2 families is 7 ÷ 2 = 3.5 pizzas each. The calculator gives the exact decimal; the decision about rounding belongs to the situation. For money, round to two decimal places and check that the rounded shares still add up to the original total. For measurements, keep one more decimal place than the measuring tool can show, and round only when you write the final figure down. For averages of a list of numbers, the average calculator handles the division and the list together.

Division by Zero and Other Errors

Division by zero has no answer in mathematics. Asking "how many groups of zero make 12?" has no sensible reply, because no number of zeros ever adds up to 12, and asking the same about zero itself — 0 ÷ 0 — could be argued to give any number at all, which is the same as giving none. This calculator therefore refuses the calculation instead of inventing an answer. It shows the message "Cannot divide by zero. Press C and try again." Press C, check which number was meant to be the divisor, and re-enter the calculation. Division by zero is not the same as dividing zero: 0 ÷ 5 = 0 is perfectly valid, because zero shared five ways is still zero. Only a zero divisor causes the error, whatever the first number is.

• Division by zero: any number ÷ 0, including 0 ÷ 0, shows the error message. Press C and start again.
• Wrong operator pressed: press the correct operator before typing the next number. The pending operation in the trail updates to the new one.
• Wrong digit typed: press Backspace to delete the last digit only, rather than clearing the whole calculation with C.
• Result looks ten times too large or too small: a decimal point was probably missed or added. Re-enter the numbers and read the display digit by digit.
• Result is negative when it should be positive: the two numbers in a subtraction or division are probably the wrong way round, or the plus-minus key was pressed by mistake.
• History entry looks wrong: the history shows each step in order, newest first, so the step where the error entered can be found and repeated correctly.

There is one more error worth naming, because it is the most common of all: pressing equals too early. In a chain, equals finishes the calculation at the current step, so 100 + 20 = gives 120 even if a further × 3 was planned. The fix is simple — the answer stays on the display, so press × 3 = next and the result is 360 — but only if you notice that equals was pressed early. Glancing at the trail before equals, and at the result line after it, turns this from a silent mistake into a visible one. The result line under the calculator restates the full calculation, such as "100 + 20 = 120", so a premature equals is easy to spot.

Everyday Uses: Shopping, Budgeting, Bills, and Cooking

A basic calculator earns its place by answering small questions quickly and reliably, dozens of times a day. The four situations below cover most of them. Each one uses only the four operations and the percent key, and each one is worked with the chained-entry behaviour of this page, so the key presses shown give exactly the answers shown. For repeated specialist calculations, such as a loan repayment or a tax estimate, a dedicated tool is quicker: the mortgage calculator, the compound interest calculator, the salary calculator, the tax calculator, and the currency converter each carry out their own full calculation, while this page stays the right tool for one-off sums.

Shopping and Unit Prices

The cheapest pack is not always the one with the lowest price tag. Divide the price by the quantity to get the unit price, and compare like with like. A 12-pack costing $9.60 is 9.60 ÷ 12 = $0.80 per item. A 500-gram bag costing $3.20 is 3.20 ÷ 5 = $0.64 per 100 grams, while a 750-gram bag costing $4.50 is 4.50 ÷ 7.5 = $0.60 per 100 grams, so the larger bag is cheaper per gram even though its price is higher. The same division settles "buy one, get one" offers: two items for $7 is 7 ÷ 2 = $3.50 each, which is only a saving if the single price is above $3.50. For a sale price, find the discount first and then subtract it: 25% off $80 is 80 × 25 % = 20 off, then 80 − 20 = 60 to pay. The discount calculator does discounts with tax and stacked offers in one place.

Budgeting and Household Bills

A household budget is a chain of subtractions from income, and this calculator handles it as one running chain. Take a monthly income of $3,200, subtract rent of $1,100, utilities of $180, groceries of $450, and transport of $200: 3,200 − 1,100 = 2,100, then 2,100 − 180 = 1,920, then 1,920 − 450 = 1,470, then 1,470 − 200 = 1,270 left. The trail shows the running balance after each bill, so a bill entered twice is visible at once. Percentages help with budget rules: a common guideline puts housing near 30% of income, and 30% of $3,200 is 3,200 × 30 % = 960. If rent is $1,100, the difference is 1,100 − 960 = 140 above that guideline figure. The guideline is only a starting point, but the arithmetic makes the comparison concrete instead of a guess.

• Start from money actually received. Budget from take-home pay, not the headline salary, or every later figure will be overstated.
• List every regular bill before the flexible spending. Rent, utilities, and transport come out first, because they cannot be skipped in a tight month.
• Work in the same period. Do not mix a weekly grocery figure with a monthly rent figure without converting one of them first: weekly × 52 ÷ 12 gives a monthly equivalent.
• Leave a remainder on purpose. A budget that spends every dollar leaves nothing for the unexpected bill, so aim for a positive remainder like the $1,270 in the example.
• Re-add the budget at the end. The bills plus the remainder must equal the income: 1,100 + 180 + 450 + 200 + 1,270 = 3,200.

Splitting Bills and Sharing Costs

Splitting a bill fairly is division, sometimes with a tip or tax added first. A meal costing $142.50 shared equally by 6 people is 142.50 ÷ 6 = $23.75 each. If a 20% tip is added first, find the tip, 142.50 × 20 % = 28.50, add it, 142.50 + 28.50 = 171.00, and then divide, 171.00 ÷ 6 = $28.50 each. When shares are unequal — one person had a main course costing $32 while the rest shared $60 of side dishes — calculate each part separately and add. Typed as one chain, 32 + 60 ÷ 3 gives 30.67 under chained entry, because 32 + 60 = 92 and 92 ÷ 3 = 30.67, which is wrong for this situation. The correct chained sequence is 60 ÷ 3 = 20 first, then 32 + 20 = 52. This is exactly the case where knowing the chained rule matters: do the division part first, then add. For unequal shares, write each person's items down first, or the division will be applied to the wrong total.

Cooking and Scaling Recipes

Recipes are ratios, and scaling a recipe is multiplication or division by the same factor for every ingredient. A recipe serving 4 people that uses 360 grams of flour needs 360 ÷ 4 = 90 grams per serving, so for 6 people it needs 90 × 6 = 540 grams. Halving the same recipe gives 360 ÷ 2 = 180 grams, and doubling it gives 360 × 2 = 720 grams. Liquid measures scale the same way: 250 millilitres halved is 250 ÷ 2 = 125 millilitres, and doubled is 250 × 2 = 500 millilitres. Baking is less forgiving than cooking, so scale by weight where the recipe gives weights, and keep the factor identical for flour, sugar, butter, and raising agents. For ratio-based scaling, such as a sauce that is 2 parts stock to 1 part cream, the ratio calculator keeps the parts in proportion.

• Find the scaling factor first. New servings ÷ old servings gives the factor: 6 ÷ 4 = 1.5, so every ingredient is multiplied by 1.5.
• Scale every ingredient, not just the main one. Forgetting the salt or the raising agent changes the result more than forgetting the flour.
• Convert units before scaling. Do not scale a mix of grams and cups in one step; convert to one unit first, then multiply.
• Round sensibly for eggs and packets. A scaled recipe needing 1.5 eggs means 1 whole egg plus 1 beaten egg measured by half, not a guess.

Health numbers follow the same arithmetic. A daily calorie target, a body mass index, or a daily water target all start with simple sums and divisions, and the dedicated tools carry the specialist formulas: the BMI calculator, the calorie calculator, the BMR calculator, the body fat calculator, the ideal weight calculator, the TDEE calculator, the water intake calculator, and the pregnancy due date calculator each add the context that a basic calculation alone cannot give.

Checking Your Answer: Mental-Math Checks

A calculator answer should be checked, not merely accepted. The quickest check is an estimate made from rounded numbers: if the estimate and the calculator agree to within a small margin, the entry was probably right; if they disagree wildly, a digit or an operation was mistyped. The second check is the reverse operation: addition is undone by subtraction, multiplication by division, and division by multiplication. A third check is the "does it make sense?" test: a discount must make a price smaller, a share must be smaller than the total, and a weekly total must be larger than any single day in it. Use at least one check for money, and two checks for any figure that will be acted on, such as an order quantity or a payment.

• Round to friendly numbers. Round 48 to 50, 19.99 to 20, and 37 to 40, and the estimate takes seconds.
• Reverse the operation. If 48 × 6 = 288, then 288 ÷ 6 must return 48. If it does not, the first entry was wrong.
• Check the size, not just the digits. An answer of 2,880 for 48 × 6 has the right digits but the wrong size, which means a decimal or a zero slipped in.
• Check money by adding the parts. Shares, discounts, and tips must add back to the original total, as in the budget check above.
• Re-enter a long chain from the history. The history shows every step, so a chain can be repeated without retyping the intermediate answers.

Common Mistakes and How to Avoid Them

Most calculator errors are entry errors, not arithmetic errors. The calculator computes exactly what was typed, so the skill is in typing what was meant. The table below lists the mistakes seen most often with a basic calculator, what each one produces, and the correct approach. Reading it once, before a long session of calculations, prevents the majority of them. The single most valuable habit is the pause before equals: read the trail, read the number on the display, and only then commit. That pause costs one second and saves the rework of an entire chain entered on a wrong first number.

• Pause before equals. Read the trail and the display together, and confirm the pending operation is the one intended.
• Enter numbers in the order of the real situation. Total first, then the amount to add, subtract, multiply, or divide by.
• Do one job per chain. A chain that mixes a discount, a tax, and a split in one run is hard to audit; split it into stages using the history.
• Keep units consistent. Do not add kilograms to grams, or weekly figures to monthly figures, without converting first.
• Write down the answer for important figures. A result that lives only on a display can be cleared by one accidental press of C.

When to Use the Scientific Calculator Instead

A basic calculator is the right tool for everyday chains: totals, shares, discounts, tips, and running balances. A scientific calculator is the right tool when the expression itself has structure that a chain cannot express. The dividing line is precedence and brackets. If a formula says "multiply first, then add", or if it contains brackets, powers, or roots, the basic calculator will follow the key presses left to right and may give a different answer from the formula. The scientific calculator applies BODMAS and PEMDAS, so it evaluates the same written expression the way a textbook does. Use it for homework, science, engineering checks, and any formula copied from a book or a website.

A clear example is 2 × (3 + 4). Under strict rules the bracket comes first: 3 + 4 = 7, then 2 × 7 = 14. Typed as a chain on this page, 2 × 3 = 6, then 6 + 4 = 10, which answers a different question. Powers are another dividing line: 3 squared is 9, and 2 to the power of 10 is 1,024, and neither has a key on a basic calculator. Roots are the same: the square root of 144 is 12, which the square root calculator gives directly. Fractions with a numerator and a denominator kept separate, and ratio problems with several parts, are also clearer in their dedicated tools, the fraction calculator and the ratio calculator.

• Use this basic calculator for: shopping totals, unit prices, tips, discounts in two steps, bill splits, running budget balances, and checking homework answers step by step.
• Use the scientific calculator for: expressions with brackets, powers, roots, and strict precedence, and formulas copied from textbooks or worksheets.
• Use the percentage calculator for: percentage increase and decrease, reverse percentages, and repeated percentage changes, where the full chain matters.
• Use the average calculator for: means of lists, where entering each value separately avoids a long error-prone chain.
• Use the fraction calculator for: adding, subtracting, multiplying, and dividing fractions while keeping numerators and denominators visible.

Choosing the right tool is not about difficulty; it is about matching the tool to the expression. A basic calculator used for a bracketed formula gives a confident wrong answer, while a scientific calculator used for a shopping total only adds buttons that are never pressed. When in doubt, work the expression both ways: once as a chain on this page, step by step, and once with precedence on the scientific calculator. If the two answers agree, the expression was safe under both rules. If they differ, the scientific result is the one that follows the written formula.

Frequently Asked Questions

What happens if I press the wrong operator?

Press the correct operator right away. Pressing a new operator before entering the next number replaces the pending one, and the trail above the display updates to show the change. Only once you start typing the next number does the previous operation get locked in by the chain.

Why does the trail above the display matter?

Because it shows the running total and the pending operation before you commit. In a chained-entry calculator the intermediate result is invisible unless displayed, so the trail is your only check that 2 + 3 really is waiting to be multiplied by 4 — and your early warning when it is not.

Why does 2 + 3 × 4 give 20 here but 14 in maths class?

This calculator evaluates chained entry left to right, like a pocket calculator. Strict BODMAS gives 14. Use the scientific calculator when you need precedence and brackets.

Can I use my keyboard?

Yes — digits, + − * /, decimal point, Enter for equals, Backspace to delete, and Escape to clear all work from the keyboard.

How do I reuse a previous answer?

Click any entry in the history list and its answer loads back into the display, ready for the next operation.

What does the % key do?

It divides the current entry by 100. So 50 % becomes 0.5, and 80 × 15 % computes 80 × 0.15 = 12.

Why does the calculator show an error on division by zero?

Because division by zero has no defined answer in mathematics — any number of groups of zero never reaches a non-zero total. The calculator refuses rather than guessing.

Can I enter negative numbers?

Yes. Press the plus-minus key to flip the sign of the number on the display, or type a number and press plus-minus before choosing an operation. For example, 5 − 8 = −3, because 8 is larger than 5, and −5 + 12 = 7. Negative results are normal in subtraction, in temperature differences, and in budgets where spending exceeds income for a period. A negative answer is not an error; it is information about direction, showing that the second quantity is the larger one.

How precise are the results?

Results are rounded to 12 significant digits, as stated in the disclaimer below. That means 1 ÷ 3 is shown as 0.333333333333 and 2 ÷ 3 is shown as 0.666666666667, with the last digit rounded. For everyday arithmetic, 12 significant digits is far more than enough: money needs two decimal places, cooking needs whole grams or millilitres, and household measurements rarely justify more than three or four significant figures. For scientific or engineering work that needs more precision, or for figures that must be exact to many places, verify the result with a dedicated tool.

Why do large numbers show commas?

Commas group the digits in thousands, so a large result can be read at a glance. The number 1234567 is shown as 1,234,567, and 1234567.89 is shown with the same grouping before the decimal point. The commas are display formatting only; they do not change the value, and they do not affect the next operation if the answer is reused from the history. If a number looks a thousand times too large, check whether a comma was misread as a decimal point, which is a common reading mistake covered in the common mistakes section above.

Can I use percent in a chain?

Yes, with one caution: the percent key only divides the current entry by 100, so its effect depends on where it appears in the chain. In 200 × 25 % =, the percent turns 25 into 0.25 and the result is 50. In 200 + 25 % =, the percent turns 25 into 0.25 and the result is 200.25, not 250, because the chain adds 0.25 to 200. To add 25% to 200, calculate 200 × 25 % = 50 first, then 200 + 50 = 250. The same caution applies to subtracting a percentage: find the percentage amount first, then subtract it in a second step.

How many history entries are kept?

The history keeps the most recent 20 calculations, newest first. Clicking any entry loads its answer back into the display, ready for the next operation, so intermediate answers never need retyping. When a 21st calculation is added, the oldest entry drops off the list. For a long multi-step problem, finish the important stages and note the answers down, rather than relying on the history to hold every step of a very long session.

What should I do if I mistype a digit?

Press Backspace to delete the last digit of the number being entered, and then type the correct digit. Backspace affects only the current entry, so the running total and the pending operation in the trail are untouched. Press C only when the whole calculation should be abandoned and started again, because C clears the running total, the operation, and the display together. On the keyboard, Backspace deletes a digit and Escape clears everything, matching the on-screen keys.

Disclaimer: This calculator is for everyday arithmetic. Results are rounded to 12 significant digits; for scientific, financial, or engineering work, verify with a dedicated tool.