Calories to Lose Weight Calculator

How many calories should you eat to lose weight? The answer is your maintenance calories minus a deficit — and the size of that deficit decides how fast you lose weight and how hard the diet feels. The calories to lose weight calculator above does the maths for you: enter your details, choose the weight-loss goal, and it shows your daily target, your macros and your weekly total.

This page explains what number it gives you and why, compares the deficit sizes, and shows you worked examples for a man and a woman so you can see exactly where your own target should sit.

Your Weight-Loss Calories in Three Steps

There is no mystery to the number. First the calculator works out your BMR with the Mifflin-St Jeor equation. Then it multiplies by your activity factor to get maintenance. Then it subtracts your chosen deficit. For most people the standard deficit is 500 calories a day, which produces about 0.5 kg of fat loss a week. If you want a gentler start, the mild option subtracts 250.

The Maths for a 30-Year-Old Man

A man aged 30, 70 kg, 175 cm, moderately active: BMR = 10 × 70 + 6.25 × 175 − 5 × 30 + 5 = 1,649 calories. Maintenance = 1,649 × 1.55 = 2,556 calories. Subtract 500 and his weight-loss target is 2,056 calories a day. His weekly intake at that target is 14,392 calories, against 17,892 at maintenance — a weekly deficit of 3,500 calories, or about 0.5 kg of fat.

The Maths for a 25-Year-Old Woman

A woman aged 25, 60 kg, 165 cm, lightly active: BMR = 10 × 60 + 6.25 × 165 − 5 × 25 − 161 = 1,345 calories. Maintenance = 1,345 × 1.375 = 1,850 calories. Subtract 500 and her weight-loss target is 1,350 calories a day. That is above the 1,200 floor, so the calculator keeps it as it is. If she chose the aggressive 1,000 deficit instead, her target would fall to 850 — and the calculator would raise it to 1,200, because eating below that without medical supervision is unsafe.

Choosing Your Deficit Size

The deficit you choose is a trade between speed and comfort. A bigger deficit loses weight faster but brings more hunger, more fatigue and more muscle loss. A smaller deficit is slower but far easier to keep doing for months — and months are what weight loss takes.

Most people should start at 500. If you have only a little weight to lose, start at 250 — a 500 deficit is a much bigger share of a small person’s maintenance, and it will feel far harder than it does for someone larger. If you have a lot to lose, 500 is still the right start; you can raise it later if progress is slow and you feel fine.

Weight-Loss Calories for Different People

The table below shows weight-loss targets at a 500 deficit for a range of people, all moderately active, so you can find the row closest to you.

Check one row: the 40-year-old man at 85 kg and 180 cm has a BMR of 10 × 85 + 6.25 × 180 − 5 × 40 + 5 = 1,780 calories. At moderate activity his maintenance is 1,780 × 1.55 = 2,759 calories, and his weight-loss target is 2,759 − 500 = 2,259 calories a day. The calculator above shows the same figures for your own numbers in seconds.

Why the Scale Does Not Move Every Week

Fat loss and scale weight are not the same thing. Your body holds water for all sorts of reasons — salty food, a hard workout, your menstrual cycle, a hot day — and 1 to 2 kg of water can hide a week of fat loss completely. That is why the scale sometimes shows nothing for two weeks and then drops a kilogram overnight. Judge your progress by the four-week trend, not by any single weigh-in, and weigh under the same conditions each time: morning, after the bathroom, before eating, in the same clothes.

• Weigh twice a week. Monday and Friday mornings, and average them.
• Compare four-week blocks. If the average is falling by about 0.5 kg a week, your target is right.
• Take measurements. Waist size often shrinks even when the scale stalls, especially if you are training.
• Expect the first week to be fast. Early losses include water, so do not expect that pace to continue.
• Plateaus are normal. Two weeks with no movement is not a failure — it is usually water, or a target that needs recalculating at your new weight.

Protecting Muscle While You Lose Weight

When you eat fewer calories than you burn, your body takes energy from fat and from muscle. How much comes from muscle depends on protein and training. Eat too little protein and skip strength training, and up to a quarter of the weight you lose can be muscle. That matters because muscle is what keeps your BMR up — lose it and your maintenance falls, making the weight harder to keep off.

• Eat 1.6 to 2.0 g of protein per kg of body weight a day. For a 70 kg person that is 112 to 140 g.
• Train with weights twice a week. Even two short sessions tell your body to keep its muscle.
• Keep the deficit moderate. A 500 deficit costs far less muscle than a 1,000 deficit.
• Do not cut protein to save calories. Cut fat and carbohydrate first; protein is the last thing to reduce.

Adjusting Your Target as You Lose Weight

Your target has an expiry date. A lighter body burns fewer calories, so the deficit shrinks as you lose weight. A man who starts at 90 kg and loses 10 kg will find his maintenance has fallen by roughly 150 calories a day. If he keeps eating the same target, his 500 deficit quietly becomes a 350 deficit, then a 200 deficit, and the weight loss slows to a stop. Recalculate your target every 5 kg lost, or once a month, using your new weight. The calorie calculator makes it a thirty-second job.

1. Enter your current weight and details in the calculator above.
2. Choose the weight-loss goal and note the new target.
3. Follow it for two weeks and watch the weekly average.
4. If your weight is not falling by about 0.25 to 0.5 kg a week, check your tracking honesty before cutting further.
5. Add a 30-minute walk before cutting more food — movement is cheaper than hunger.

Related tools: your resting burn from the BMR calculator, your full daily burn from the TDEE calculator, and your weight category from the BMI calculator. The National Heart, Lung, and Blood Institute explains safe rates of weight loss and how to keep the weight off.

At a Glance

Keep the reference figures below handy while you plan.

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

1. Enter your sex, age, weight and height in the calculator above.
2. Choose the activity level that honestly matches your week.
3. Pick your goal and note your daily target and your macro grams.
4. Plan three days of meals that hit the target, then repeat them.
5. 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?

Subtract 500 from your maintenance calories for about 0.5 kg of loss a week, or 250 for about 0.25 kg. A 30-year-old man maintaining on 2,556 calories would eat 2,056 a day; a 25-year-old woman maintaining on 1,850 would eat 1,350 a day.

Is a 1,000-calorie deficit safe?

Only for short periods and with medical guidance. A 1,000 deficit loses about 1 kg a week but brings strong hunger, fatigue and a higher share of muscle loss. Most people do far better on 500 a day for months than on 1,000 a day for three weeks.

What is the lowest calorie intake for weight loss?

As a rule, 1,200 calories a day for women and 1,500 for men. Below those floors it is very hard to get enough protein, vitamins and minerals. The calculator enforces those floors and raises any lower target automatically.

How long will it take to lose 10 kg?

At a 500-calorie deficit, about 20 weeks. At a 250 deficit, about 40 weeks. The first week is often faster because of water loss, and plateaus of two weeks are normal — judge by the four-week trend, not single weigh-ins.

Do I need to exercise to lose weight on a calorie deficit?

You can lose weight by diet alone, but exercise makes it easier and healthier: it burns extra calories, protects muscle, and improves fitness and mood. A daily 30-minute walk adds about 150 calories of burn without making you hungry.

Why did my weight loss stop after two months?

Usually because your lighter body now burns fewer calories, so your original deficit has shrunk. Recalculate your target with your new weight. A 10 kg loss typically lowers maintenance by about 150 calories a day, which is often the whole plateau.

Disclaimer: This calculator provides estimates for general information only and is not medical or dietary advice. Weight loss can be unsafe for some people, including anyone pregnant, under 18, or with a history of eating disorders. Consult a doctor or registered dietitian before starting a weight-loss plan.