BMR and TDEE Calculator
Basal rate and daily calories, by three equations.
BMR and TDEE Calculator estimates basal metabolic rate with Mifflin-St Jeor, the revised Harris-Benedict equation and, given a body fat figure, Katch-McArdle, then shows how far apart the three land. An activity factor turns the chosen one into daily expenditure, with calorie targets and the weekly rate each implies. Nothing is uploaded.
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This is a calculation tool, not medical advice. The result is an estimate from a published formula and cannot account for your individual circumstances. Talk to a healthcare professional about anything that matters.
How to use BMR and TDEE Calculator
- Enter age, sex, height and weight, and a body fat percentage if you have one.
- Pick an activity level and the equation you want the targets built on.
- Compare the three estimates, then read the calorie targets.
Questions about BMR and TDEE Calculator
Which of the three equations should I use?
Mifflin-St Jeor is the usual default and the more accurate of the two height-and-age equations on modern populations. Katch-McArdle is better if you have a trustworthy body fat measurement, because it works from lean mass and needs no sex term at all. The revised Harris-Benedict is here mostly to show how much the answer moves with the choice.
How accurate is a BMR estimate?
For most people it lands within about ten per cent of a measured resting rate, which on a 1,600 kcal estimate is a spread of some 300 kcal. Indirect calorimetry is the only way to know your own figure. All three equations were fitted on adults, so the page declines to run under 18: a growing body spends energy on growing, and none of them has a term for it. Treat this as a starting point and adjust it from what the scales actually do over a few weeks.
Why does the activity factor matter so much?
Because it multiplies the whole basal rate rather than adding to it. Moving from lightly active to moderately active raises a 1,600 kcal BMR by nearly 300 kcal a day, which is larger than the gap between any two of the equations. Most people choose a level one step too high.
Is losing a kilogram a week realistic?
It needs a deficit of roughly 1,100 kcal a day, which for many people puts the daily target below their own basal rate. The tool marks targets that fall under the levels usually considered sensible without supervision. A slower rate is generally easier to hold and easier to keep.
Does weight loss stay linear?
No, and the table quietly assumes it does. The 7,700 kcal per kilogram behind those figures is a fair approximation for fat tissue but not for months of dieting: a lighter body needs less energy to run, so the same deficit buys less each week and the straight line bends.
Is BMR and TDEE Calculator really free, with no limits?
Yes. There is no account, no daily cap, no file-size tier and no watermark, because there is no server cost to recover. The site is funded by clearly disclosed partner recommendations on the Partners page, never by metering the tools.
Are my files or text uploaded when I use BMR and TDEE Calculator?
No. Everything is processed by JavaScript running in your browser, on your device. You can verify it: open your browser's developer tools, switch to the Network tab, and use the tool. You will see no request carrying your data — because there is nowhere for it to go.