BMR Calculator
Work out what your body burns at complete rest, on five published formulas. No account needed.
Your numbers
Unlocks Katch-McArdle and Cunningham, which work from lean mass.
Enter your details to see your resting burn
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Your resting burn is the easy half. Forte logs every set you lift, so the training half stops being a guess.
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How it works
BMR — basal metabolic rate — is what your body spends staying alive: heart, lungs, brain, kidneys, keeping you warm. It is measured lying still, awake, having not eaten. It is the floor under your day, not your day: nobody burns only their BMR, which is why the table on the right multiplies it out to a whole day at each activity level.
Mifflin-St Jeor (Mifflin & St Jeor, 1990) is the default — fitted on modern bodies and usually within about 10 % for people who are not very lean or very heavy. Harris-Benedict (Harris & Benedict 1919, revised by Roza & Shizgal, 1984) is the older standard and reads a little higher. Schofield (1985) is the WHO/FAO/UNU table, which uses weight and an age band and no height at all. Katch-McArdle (1996) and Cunningham (1980) work from lean body mass, so they need a body-fat percentage before they can answer — enter one and they unlock. For a lean, muscular lifter they are usually the closest of the five, because 80 kg of muscle and 80 kg that is mostly not do not burn the same.
The activity multipliers in the table are the standard set: Sedentary ×1.2 (desk job, little exercise) · Light ×1.375 (1–3 days a week) · Moderate ×1.55 (3–5 days a week) · Active ×1.725 (6–7 days a week) · Very active ×1.9 (hard daily training or a physical job). Read the row that matches your whole week. If you want the macro split that goes with it, the TDEE calculator carries these same numbers across.
These are estimates, not medical advice. Every formula here is a population average, and real people sit either side of it — thyroid function, medication, sleep and body composition all move the number. Treat it as a starting point rather than a measurement. If you are managing a medical condition, are pregnant, or are eating below about 1,200 kcal a day, talk to a doctor or a registered dietitian first. See our disclaimer.