Calorie Calculator
BMR, TDEE and daily targets for every goal — plus a macro split, using Mifflin-St Jeor.
An estimate for general information, not medical or dietary advice. Speak to a doctor or dietitian before making significant changes, particularly if you have a health condition.
How to Use
- 1. Choose metric or imperial units and enter your age and sex.
- 2. Enter your current weight and height.
- 3. Pick the activity level that honestly matches your week.
- 4. Read the calorie target for your goal, and the macro split if you want one.
What These Numbers Can and Cannot Tell You
BMR is what your body spends at complete rest — breathing, circulating blood, maintaining temperature. It is typically 60 to 70% of everything you burn in a day. Multiplying it by an activity factor gives TDEE, and that is the figure to eat against. The Mifflin-St Jeor equation used here predicts resting expenditure more accurately than the older Harris-Benedict formula, and usually lands within about 10% of a measured value.
Most people overestimate their activity level, which is where these calculations go wrong in practice. The multiplier is meant to cover your whole week including the sedentary days, not the three good gym sessions. If you have a desk job and train four times a week, "moderately active" is honest; "very active" describes physical labour or twice-daily training.
The goal targets come from the rough figure that a kilogram of body fat stores around 7,700 calories. The arithmetic is sound but the body adapts — expenditure falls somewhat as you lose weight, partly from carrying less mass and partly from moving less without noticing. A deficit that worked for the first six weeks usually needs revisiting.
Of the macros, protein is the one worth actually hitting; it preserves muscle in a deficit and is the most satiating of the three. The carb and fat split is largely preference, and the best ratio is whichever one you can keep to.
Treat the output as a hypothesis rather than a prescription: eat at it for two or three weeks, track your weight, and adjust based on what happens rather than what the formula predicted.
Related: BMI Calculator, Percentage Calculator, and Weight Converter.
Frequently Asked Questions
What is the difference between BMR and TDEE?
BMR is what your body burns at complete rest just staying alive — breathing, circulation, keeping warm. TDEE is that figure multiplied by an activity factor to account for movement, exercise and digestion. TDEE is the number you eat against; BMR is a floor you should not go below.
Which formula does this use?
Mifflin-St Jeor, which has been shown to predict resting expenditure more accurately than the older Harris-Benedict equation for most people. It works from weight, height, age and sex, and typically lands within about 10% of a measured value.
How accurate is a calculated calorie target?
It is a starting estimate, not a measurement. Two people with identical stats can differ by several hundred calories a day because of muscle mass, thyroid function, genetics and how much they fidget. Treat the number as a hypothesis: eat at it for two or three weeks, track your weight, and adjust based on what actually happens.
Why is 0.5 kg a week about 550 calories a day?
Because a kilogram of body fat stores roughly 7,700 calories, so half of that spread across seven days is about 550 a day. The arithmetic is sound but the body adapts — expenditure drops somewhat as you lose weight, so a deficit that worked initially usually needs revisiting.
Should I eat below my BMR to lose faster?
It is generally a bad idea. Very low intakes make it hard to get enough protein and micronutrients, tend to cost you muscle alongside fat, and are difficult to sustain, which is why they so often end in regain. The calculator flags any target that falls below your BMR.
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