Calorie calculator
Estimates how many calories your body uses in a day, and what to eat for your goal. Uses the Mifflin-St Jeor equation, which is the one most commonly used clinically because it outperforms the older Harris-Benedict formula in validation studies.
Built by Mubashir. Uses a published standard formula, named below. Not medical advice — see the limitations section.
About you
Daily calorie target
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BMR — at complete rest
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TDEE — maintenance
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Protein
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Carbohydrate
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Fat
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Show the working
—A screening estimate, not a prescription. Individual energy needs vary by ten to fifteen percent from any equation's prediction, and more in the presence of thyroid conditions, medication, pregnancy or a history of dieting. If you have a medical condition, are pregnant or breastfeeding, or have any history of disordered eating, speak to a doctor or registered dietitian before changing your intake.
BMR and TDEE
BMR is your basal metabolic rate — the energy your body uses lying completely still, keeping your heart beating, lungs working and temperature stable. It typically accounts for around 60 to 70% of total daily energy use, which surprises people who assume exercise dominates.
TDEE is total daily energy expenditure: BMR multiplied by an activity factor. This is your maintenance level, the intake at which your weight stays roughly stable.
The equation used here is Mifflin-St Jeor:
BMR = 10w + 6.25h − 5a + 5 (male) or −161 (female)
where w is weight in kilograms, h is height in centimetres and a is age in years.
The activity multiplier is the weakest link
Everything above the BMR calculation is an estimate layered on an estimate, and the activity factor is where most of the error enters. People consistently overestimate how active they are.
The categories are also blunt. Someone who trains hard four times a week but sits at a desk for the remaining hundred and sixty hours may burn less overall than someone who never exercises but works on their feet. Non-exercise activity — walking, standing, fidgeting — varies enormously between individuals and is invisible to this kind of calculation.
If you are unsure, pick the lower category. Overestimating your expenditure is the more common error and the one that quietly stalls progress.
The deficit and why 0.5 kg a week
A kilogram of body fat stores roughly 7,700 calories, so a daily deficit of about 500 calories corresponds to half a kilogram a week. That figure is a useful planning anchor rather than a physical law — real weight loss is not linear, and the body adapts.
As you lose weight, your BMR falls, because there is less tissue to maintain. Activity expenditure often falls too, partly because moving a lighter body costs less and partly through unconscious reductions in spontaneous movement. This is why a deficit that worked initially stops working, and why the calculator's numbers should be recalculated as your weight changes rather than treated as fixed.
Faster is not better. Aggressive deficits increase the share of weight lost as lean tissue rather than fat, and are harder to sustain, which is the variable that actually predicts outcomes.
About the macro split
The protein figure uses roughly 1.6 grams per kilogram of body weight, which sits in the range commonly recommended for people who are active or in a deficit. Fat is set at about 27% of calories, comfortably above the minimum needed for hormone production. Carbohydrate fills the remainder.
This is one reasonable split among many, not an optimum. Adherence matters more than composition for most people most of the time.
Frequently asked questions
What is TDEE?
Total daily energy expenditure — all the calories your body uses in a day, including basal metabolism, digestion, exercise and general movement. It is the intake at which your weight stays stable.
What is the difference between BMR and TDEE?
BMR is what your body uses at complete rest. TDEE is BMR plus everything else you do, which is why it is always higher.
How many calories to lose one kilogram?
Roughly 7,700 calories of deficit corresponds to a kilogram of fat, so around 500 a day gives about half a kilogram a week. Treat this as a planning figure rather than a precise rule.
Why is my calculated target different from another site?
Different calculators use different equations. Mifflin-St Jeor, Harris-Benedict and Katch-McArdle produce different figures, and activity multipliers vary too. Any of them is an estimate with meaningful error.
How accurate is this?
Predicted energy needs typically fall within ten to fifteen percent of actual for most people, but individual variation is real. Use the figure as a starting point and adjust based on what actually happens over two to three weeks.
Should I recalculate as my weight changes?
Yes. Your BMR falls as you lose weight, so a target set at your starting weight becomes less of a deficit over time. Recalculating every few kilograms keeps it honest.