Free tool
Free BMR Calculator
Your basal metabolic rate is the energy your body burns at complete rest — before any movement, digestion or exercise.
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Please note: These calculators give general estimates from population-level formulas. They are not medical advice, and they may not reflect people on GLP-1 medications precisely — appetite suppression, rapid weight loss, and lean-mass changes all shift the real numbers. Always consult your prescriber for personalized guidance.
The Mifflin-St Jeor equation
BMR (men) = 10 × weight in kg + 6.25 × height in cm − 5 × age + 5. For women the final term is −161 instead of +5.
Mifflin-St Jeor is the equation most dietitians default to because it estimates resting energy expenditure more accurately across modern populations than the older Harris-Benedict formula.
To get the calories you actually burn in a day, multiply BMR by an activity factor — that is your TDEE.
Why BMR moves while you're on a GLP-1
BMR is driven largely by lean mass. Lose muscle and your resting burn falls with it, which is one reason weight regain after stopping a GLP-1 is so common.
Recalculate every few kilos, and pair it with adequate protein and resistance training so the number falls as little as possible for the weight you lose.