Calorie Calculator
Daily calories to maintain, lose or gain weight
An estimate, not a prescription. Two people with identical stats can differ by roughly 10% either way, so treat the number as a starting point and adjust it against what the scale actually does over a few weeks.
Calories for every goal
| Goal | Calories / day | Change | Expected rate |
|---|
Macronutrient split
| Approach | Protein | Carbs | Fat | P/C/F % |
|---|
How to Use
- 1Pick metric or imperial, then enter your height and weight.
- 2Add your age and sex, because both change resting energy a lot.
- 3Choose the activity level that matches a normal week, not your best one.
- 4Read maintenance calories, then open the goal table for a deficit or surplus.
The Formulas
- Mifflin-St Jeor · men10w + 6.25h − 5a + 5
- Mifflin-St Jeor · women10w + 6.25h − 5a − 161
- Katch-McArdle370 + 21.6 × lean mass
- Daily caloriesBMR × activity factor
- 1 lb of fat≈ 3,500 kcal
Quick Examples
Tap an example to load it above.
Everything about the Calorie Calculator
What the number means, where it comes from, and how far to trust it.
This calorie calculator estimates how much energy your body uses in a day. It works out your BMR (the calories you would burn lying still for 24 hours), multiplies it by an activity factor to give your TDEE, and then shows the intake for every common goal from steady weight loss to deliberate gain.
Where the BMI calculator answers "is my weight in a healthy range for my height", this page answers a different question entirely: "how much energy does my body actually use". The two are unrelated calculations. BMI knows nothing about your activity, and this page knows nothing about your weight category.
This is an estimate, not a prescription. The equations are fitted to population averages and real expenditure varies by roughly ±10% between people with identical height, weight, age and sex: thyroid function, sleep, muscle mass and fidgeting all move the number. Use it as a starting point, then adjust based on what the scale does over two to three weeks. It is not medical or dietary advice, and if you have a health condition, are pregnant, or are under 18, speak to a doctor or dietitian first.
BMR, TDEE and the activity factor
BMR is usually 60 to 70% of everything you burn. Digestion accounts for roughly another 10%, and the rest is movement, both deliberate exercise and everything else, from walking to the kitchen to tapping your foot. The activity multiplier bundles all of that into one number.
| Activity level | Factor | Roughly means |
|---|---|---|
| Sedentary | × 1.2 | Desk job, little or no exercise |
| Lightly active | × 1.375 | Light exercise 1 to 3 days a week |
| Moderately active | × 1.55 | Moderate exercise 3 to 5 days a week |
| Very active | × 1.725 | Hard exercise 6 to 7 days a week |
| Extra active | × 1.9 | Twice-daily training or a physical job |
Most people overestimate here. Three gym sessions a week alongside a desk job is lightly to moderately active, not very active, and picking one level too high inflates your target by several hundred calories a day, which is enough to cancel an entire deficit.
Which formula should you pick?
- 1Mifflin-St Jeor (the default)
Published in 1990 and the most accurate of the three for the general population. It is what dietitians reach for first, and what this page uses unless you change it.
- 2Revised Harris-Benedict
The 1919 original, revised in 1984. Still widely quoted, but it tends to run slightly high, mostly useful when you need to match a figure someone else calculated with it.
- 3Katch-McArdle (if you know your body fat)
Works from lean mass rather than total weight, so it ignores height and sex completely. For a lean, muscular person it is the most accurate of the three; for everyone else the body-fat guess it depends on introduces more error than it removes.
The 3,500-calorie rule, and its limits
A pound of body fat stores roughly 3,500 calories, so a 500-calorie daily deficit is often quoted as one pound a week. That works well at first. Over months it overstates the loss, because a lighter body burns fewer calories and metabolism adapts, which is why the rate slows even when the diet does not change. Expect the first weeks to track the prediction and later weeks to lag it.
How low is too low
The targets in the goal table are flagged when they fall below about 1,500 calories a day for men or 1,200 for women. Those are not physiological cliffs. They are the point at which getting enough protein, fibre, vitamins and minerals from food becomes genuinely difficult. Very low intakes also cost you muscle alongside fat. A slower deficit that you actually keep to beats an aggressive one you abandon.
Protein, carbs and fat
Total calories decide whether weight moves; the split decides how you feel and what you keep. Protein is the one worth protecting, since it preserves muscle in a deficit and is the most filling of the three. The macronutrient table gives grams for three common approaches at your maintenance figure; scale them proportionally if you pick a deficit or surplus.
Frequently Asked Questions
How many calories should I eat a day?
Start from the maintenance figure at the top of this page, which is what your body burns at your current weight and activity level. To lose weight, subtract 250 to 500 calories a day; to gain, add the same. The goal table shows every option with the weekly rate it should produce, so you can pick the pace that suits you rather than guessing.
What is the difference between BMR and TDEE?
BMR is what you would burn lying completely still for 24 hours, covering breathing, circulation, brain and organ function. TDEE is BMR multiplied by an activity factor, so it includes digestion, exercise and all the incidental movement of a normal day. TDEE is the number to eat to, never BMR.
Which BMR formula is the most accurate?
Mifflin-St Jeor for most people, which is why it is the default here. Katch-McArdle can beat it if you genuinely know your body-fat percentage, because it works from lean mass, but a guessed body-fat figure introduces more error than it removes. Revised Harris-Benedict is older and tends to read slightly high.
Why do the goal calories say 500 fewer equals one pound a week?
Because a pound of body fat stores roughly 3,500 calories, and 500 × 7 days is 3,500. It is a good approximation for the first few weeks. Over several months it overstates the loss, since a lighter body burns less and metabolism adapts, so expect the real rate to slow even if your intake does not change.
How accurate is this calorie calculator?
The equations are fitted to population averages, and real energy expenditure varies by roughly 10% either way between people with identical height, weight, age and sex. Treat the figure as a starting point: eat to it for two to three weeks, track your weight, and adjust by 100 to 200 calories if the scale is not moving the way the table predicts.
What activity level should I choose?
Pick the one that describes a normal week, not your best week. Three gym sessions alongside a desk job is lightly to moderately active, not very active. This is the single most common mistake, because one level too high can add several hundred calories a day and quietly cancel an entire deficit.
Why is a low calorie target flagged as a warning?
Targets below roughly 1,500 calories a day for men or 1,200 for women are flagged because getting enough protein, fibre, vitamins and minerals from food becomes genuinely difficult at that level, and very low intakes cost muscle alongside fat. The number is still shown rather than hidden, but a diet that low should be supervised by a doctor or dietitian.
Is this calorie calculator free, and is my data stored?
It is completely free with no sign-up, and every calculation runs inside your browser, so your age, height and weight are never sent to a server or saved anywhere. This page is for general information only and is not medical or dietary advice.