How Many Calories Should I Eat a Day?
Most adults need somewhere between 1,800 and 3,000 calories a day, but the honest answer is that your number depends on your body and your life. A 25-year-old woman who walks to work needs far fewer calories than a 40-year-old man who trains five days a week, even if they weigh the same. The only way to know your number is to work it out from your own age, weight, height, sex and activity level — which is exactly what the calorie calculator above does in a few seconds.
This page explains where that number comes from, shows you the maths step by step, and gives you the typical ranges for men and women at every activity level. By the end you will know your daily target, how to change it for weight loss or muscle gain, and the mistakes that make most people’s estimates wrong.
The Short Answer: Typical Daily Calories
If you want a quick ballpark before doing the maths, the US Dietary Guidelines give these ranges for adults. They are averages for a healthy weight, so treat them as a starting point, not a prescription.
| Group | Sedentary | Moderately active | Active |
|---|---|---|---|
| Women 19–30 | 1,800–2,000 | 2,000–2,200 | 2,400 |
| Women 31–50 | 1,800 | 2,000 | 2,200 |
| Women 51 and over | 1,600 | 1,800 | 2,000–2,200 |
| Men 19–30 | 2,400 | 2,600–2,800 | 3,000 |
| Men 31–50 | 2,200 | 2,400–2,600 | 2,800–3,000 |
| Men 51 and over | 2,000 | 2,200–2,400 | 2,400–2,800 |
Notice how wide the bands are. Two women of the same age can differ by 600 calories a day purely because one walks 10,000 steps and the other sits at a desk. That is why a personal calculation beats a generic chart every time. Enter your own numbers in the calorie calculator above and you get a target built for you, not for an average person who does not exist.
How Your Daily Number Is Built
Your daily calorie need has two parts. The first is your basal metabolic rate (BMR) — the energy your body burns at complete rest to keep you alive: breathing, circulation, body temperature, cell repair. The second is everything else you do: walking, working, exercising, digesting food, even fidgeting. Add the two together and you get your total daily energy expenditure (TDEE), which is your maintenance calorie level.
Step 1 — Your BMR
BMR is calculated with the Mifflin-St Jeor equation, the formula most dietitians use today. For men it is 10 × weight in kg + 6.25 × height in cm − 5 × age + 5. For women the last term is −161 instead of +5, because women typically carry less muscle at the same weight. A 30-year-old man who weighs 70 kg and stands 175 cm tall has a BMR of 10 × 70 + 6.25 × 175 − 5 × 30 + 5 = 1,649 calories a day. That is what he burns lying still in bed all day. To see your own resting burn, try the BMR calculator.
Step 2 — Your Activity Multiplier
BMR is then multiplied by an activity factor. A desk worker who barely moves multiplies by 1.2; someone who trains hard six days a week multiplies by 1.725. Picking the right factor matters more than getting your BMR exactly right, because the factor swings your result by hundreds of calories.
| Activity level | Multiplier | What it means |
|---|---|---|
| Sedentary | 1.2 | Desk job, little or no exercise |
| Lightly active | 1.375 | Light exercise or sport 1–3 days a week |
| Moderately active | 1.55 | Moderate exercise 3–5 days a week |
| Very active | 1.725 | Hard exercise 6–7 days a week |
| Extra active | 1.9 | Physical job plus hard training, or twice-daily training |
Most people overestimate their activity. If you go to the gym three times a week but sit for the other nine waking hours, you are lightly or moderately active at best — not very active. When in doubt, choose the lower factor and watch your weight for two weeks; the scale will tell you if the number was right.
Worked Example: A 30-Year-Old Man
Take a man aged 30, weighing 70 kg, 175 cm tall, moderately active, who wants to maintain his weight. His BMR is 1,649 calories. Multiply by 1.55 for moderate activity and his maintenance level is 2,556 calories a day. The calculator above shows this as its default result, along with a macro split and a weekly total.
| Measure | Amount |
|---|---|
| BMR (at complete rest) | 1,649 kcal/day |
| TDEE (maintenance, × 1.55) | 2,556 kcal/day |
| Weekly total at maintenance | 17,892 kcal/week |
| Protein (30% of calories) | 192 g/day |
| Carbohydrates (40% of calories) | 256 g/day |
| Fat (30% of calories) | 85 g/day |
The macro split uses a balanced 30% protein, 40% carbohydrate, 30% fat mix. Protein works out at 192 g because each gram of protein carries 4 calories: 2,556 × 30% ÷ 4 = 192. Carbohydrates also carry 4 calories a gram, giving 256 g, while fat carries 9 calories a gram, giving 85 g. If you prefer a higher-protein plan, the calculator offers a 40% protein split as well.
Worked Example: A 25-Year-Old Woman
Now a woman aged 25, weighing 60 kg, 165 cm tall, lightly active. Her BMR is 10 × 60 + 6.25 × 165 − 5 × 25 − 161 = 1,345 calories a day. Multiply by 1.375 for light activity and her maintenance is 1,850 calories a day. That is 700 calories less than the man in the previous example — mostly because she is lighter and shorter, and partly because the female formula subtracts 161 instead of adding 5. Same method, very different answer, which is why copying someone else’s calorie target never works.
Adjusting Your Number for Your Goal
Maintenance is the starting point. To lose weight you eat below it; to gain weight you eat above it. A deficit of 500 calories a day removes about 3,500 calories a week, which is roughly 0.5 kg of body fat. A smaller deficit of 250 a day loses about 0.25 kg a week and is easier to live with. The table below uses the 30-year-old man from the worked example, whose maintenance is 2,556 calories.
| Goal | Daily calories | Expected pace |
|---|---|---|
| Aggressive loss (−1,000) | 1,556 kcal | About 1 kg/week — short term only |
| Weight loss (−500) | 2,056 kcal | About 0.5 kg/week |
| Mild loss (−250) | 2,306 kcal | About 0.25 kg/week — easiest to sustain |
| Maintain | 2,556 kcal | Weight stable |
| Mild gain (+250) | 2,806 kcal | Slow lean gain |
| Gain (+500) | 3,056 kcal | About 0.5 kg/week gain |
Never drop below 1,200 calories a day if you are a woman, or 1,500 if you are a man, without medical supervision. Below those floors it becomes very hard to get enough protein, vitamins and minerals, and the risk of muscle loss, fatigue and hormonal problems rises sharply. The calculator enforces those floors automatically and warns you when a target has been raised to the safe minimum.
What Affects Your Number Most
- Body weight. The single biggest factor. A 90 kg person burns roughly 200 calories a day more at rest than a 70 kg person of the same height and age, because there is simply more tissue to maintain.
- Muscle mass. Muscle burns more energy at rest than fat does. Two people at 80 kg can have BMRs 200 calories apart if one is lean and muscular and the other carries more fat.
- Age. BMR falls by about 5 calories a year in the formula — small per year, but 150 calories a day between age 25 and 55. Much of that fall is really muscle loss, which strength training can slow.
- Activity. The difference between sedentary (×1.2) and extra active (×1.9) is nearly 60% of your BMR — over 1,000 calories a day for the man in our example.
- Sex. At the same weight, height and age, men burn about 160 calories a day more than women, reflecting higher average muscle mass.
- Food itself. Digesting food burns roughly 10% of what you eat — more for protein, less for fat. It is already included in the activity multiplier, not added on top.
Common Mistakes When Estimating Calories
- Choosing too high an activity level. The most common error. Three gym sessions a week is moderately active, not very active.
- Counting exercise twice. If your multiplier already includes your workouts, do not add the calories your watch says you burned on top.
- Forgetting drinks and snacks. A sugary coffee and two handfuls of nuts can add 400 calories that never make it into a food diary.
- Using a target from someone else. Your friend’s 2,000 calories may be your 2,500, or your 1,700.
- Ignoring weekends. Eating at maintenance all week then adding 1,500 calories on Saturday wipes out a 250-a-day deficit entirely.
- Never rechecking. As you lose weight your BMR falls, so a target that worked at 90 kg is too high at 80 kg. Recalculate every 5 kg lost.
How to Use the Calculator Above
- Select your sex, then enter your age, weight and height.
- Choose the activity level that honestly matches your week.
- Pick your goal: lose weight, maintain, or gain.
- Choose a macro split — balanced is a good default.
- Read your daily target, your BMR, your weekly total and your macro grams.
- Follow the target for two weeks, weigh yourself twice a week, and adjust by 100–200 calories if your weight is not moving as expected.
Related tools: check your BMR for the resting part of the maths, your TDEE for a deeper activity breakdown, and the calorie calculator itself whenever your weight changes. The World Health Organization fact sheet on obesity and overweight explains why getting this number right matters for long-term health.
Summary
Keep the reference figures below handy while you plan.
| Macro split (2,556 kcal) | Protein | Carbohydrates | Fat |
|---|---|---|---|
| Balanced — 30/40/30 | 192 g | 256 g | 85 g |
| High protein — 40/30/30 | 256 g | 192 g | 85 g |
| Low carb — 40/20/40 | 256 g | 128 g | 114 g |
What to remember
- Your maintenance calories are your BMR times your activity factor — everything else is built on that number.
- A 500-calorie daily deficit loses about 0.5 kg a week; a 250 deficit loses about 0.25 kg.
- Never eat below 1,200 calories a day (women) or 1,500 (men) without medical supervision.
- Protein should be 1.6 to 2.0 g per kg of body weight a day when you train.
- Recalculate your target every 5 kg of weight lost, because a lighter body burns fewer calories.
Your checklist
- Enter your sex, age, weight and height in the calculator above.
- Choose the activity level that honestly matches your week.
- Pick your goal and note your daily target and your macro grams.
- Plan three days of meals that hit the target, then repeat them.
- Weigh yourself twice a week and compare the weekly averages.
Mistakes to avoid
- Choosing too high an activity level — three gym sessions a week is moderately active, not very active.
- Counting exercise twice by adding watch calories on top of the activity multiplier.
- Forgetting drinks, sauces and cooking oil, which can add hundreds of calories.
- Judging progress by one weigh-in instead of the four-week trend.
- Never recalculating after losing weight, so the old target quietly becomes too high.
Frequently Asked Questions
How many calories should I eat a day to lose weight?
Take your maintenance calories and subtract 500 for about 0.5 kg of loss a week, or 250 for about 0.25 kg a week. For the 30-year-old man in our example, maintenance is 2,556 calories, so a weight-loss target is 2,056 calories a day. Never go below 1,200 calories (women) or 1,500 (men) without medical supervision.
How many calories does the average woman need a day?
Most adult women need 1,800 to 2,400 calories a day depending on age and activity: about 1,800 when sedentary, 2,000 when moderately active, and 2,400 when very active. Younger women need more than older women at the same activity level.
How many calories does the average man need a day?
Most adult men need 2,200 to 3,000 calories a day: about 2,200 to 2,400 when sedentary, 2,400 to 2,800 when moderately active, and up to 3,000 when very active. Taller and heavier men sit at the top of those ranges.
Do I need fewer calories as I get older?
Yes, gradually. BMR falls by roughly 5 calories a year in the Mifflin-St Jeor formula, and muscle loss with age adds to the drop. Between 25 and 55 that is about 150 calories a day. Strength training twice a week slows the fall considerably.
Should I eat back the calories I burn exercising?
Usually no. The activity multiplier in the calculation already includes your exercise, so adding workout calories on top counts them twice. If you use the sedentary multiplier and add exercise separately, that is the one case where adding them back makes sense — but do it with the same method every day.
Why does the calculator give a different number from my fitness watch?
Watches estimate burn from heart rate and movement, and they commonly overestimate by 10 to 30 percent. The calculator uses a validated formula and your activity level instead. Use the calculator number as your target and the scale over two weeks as your judge.
Disclaimer: This calculator provides estimates for general information only and is not medical or dietary advice. Calorie needs vary with health conditions, medicines and body composition. Consult a doctor or registered dietitian before starting a weight-loss or muscle-gain plan, especially if you have a medical condition.