TDEE and BMR calculator — daily calorie needs
Estimate what your body burns at complete rest (BMR) and across a normal day (TDEE), then see the daily calorie figures for losing, holding or gaining weight.
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Mifflin-St Jeor (1990) — the current best general estimate.
Light exercise 1–3 days a week
These are estimates from population averages, and individuals vary by roughly ±10% for reasons no equation captures. Treat the number as a starting point: track your actual weight over two or three weeks and adjust from what really happens.
How to use
- Enter your details. Weight, height, age and sex — all four affect the estimate.
- Choose a formula. Mifflin-St Jeor is the best general choice. Katch-McArdle is more accurate if you have a reliable body-fat figure.
- Set your activity level. Be honest here; overstating it is the most common source of error.
- Pick a goal. The table shows the daily calorie target for each rate of change.
Questions
What is the difference between BMR and TDEE?
BMR is what you would burn lying still all day — breathing, circulation, keeping warm. TDEE is BMR multiplied by an activity factor, and represents what you actually burn. TDEE is the number to eat against.
Which formula should I use?
Mifflin-St Jeor (1990) is the most accurate for the general population and is what most dietitians use. Harris-Benedict is older and reads slightly high. Katch-McArdle works from lean mass, so it beats both — but only if your body-fat percentage is measured properly rather than guessed.
Why do 500 fewer calories mean half a kilo a week?
A kilogram of body fat holds roughly 7,700 kcal, so a 500 kcal daily deficit is about 3,500 a week, or just under half a kilo. In practice the loss is slower than the arithmetic predicts, because your body adapts and because activity tends to fall as intake does.
How accurate is this?
Individual metabolic rates vary by roughly ±10% from what any equation predicts, for reasons including thyroid function, gut microbiome and genetics. Use the number as a starting point, then track your weight over two to three weeks and adjust from what actually happens.
Methodology & sources
How this is calculated
Basal metabolic rate is estimated with the Mifflin–St Jeor equation (1990): 10 × weight kg + 6.25 × height cm − 5 × age + 5 for men, and the same with −161 for women. Total daily energy expenditure multiplies that by an activity factor from 1.2 (sedentary) to 1.9 (very heavy training). The Harris–Benedict and Katch–McArdle equations are offered as alternatives; Katch–McArdle uses lean mass and so needs a reliable body-fat figure.
Assumptions
- Activity multipliers are conventional planning figures rather than measured values, and are the least precise part of the calculation.
- Mifflin–St Jeor was derived from 498 healthy adults aged 19–78, both normal-weight and obese.
Limitations
- A systematic review of predictive equations found Mifflin–St Jeor the most reliable of those tested, but even it predicted measured resting metabolic rate to within 10% for only about 80% of non-obese adults — so a meaningful minority of people fall outside that band.
- The equations were derived from healthy adults and are less reliable in illness, pregnancy, or at the extremes of body composition.
- Use the figure as a starting point and adjust from what your weight actually does over two to three weeks.
Sources
- Mifflin MD, St Jeor ST, Hill LA, Scott BJ, Daugherty SA, Koh YO. “A new predictive equation for resting energy expenditure in healthy individuals.” Am J Clin Nutr 1990;51(2):241–247 American Journal of Clinical Nutrition
- Frankenfield D, Roth-Yousey L, Compher C. “Comparison of predictive equations for resting metabolic rate in healthy nonobese and obese adults: a systematic review.” J Am Diet Assoc 2005;105(5):775–789 Journal of the American Dietetic Association
Sources last checked 30 July 2026. Estimates for general information only — not medical advice, and no substitute for a qualified clinician.
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