How Many Calories Does Your Body Burn at Rest?
Enter your sex, weight, height, and age to calculate your Basal Metabolic Rate using the Mifflin-St Jeor formula — and see your calorie needs at every activity level.
Your BMR accounts for 60–75% of all calories you burn daily — even on a rest day.
60–75%
of total daily calorie burn comes from BMR — even at rest
×1.55
activity multiplier for someone exercising 3–5 days per week (moderate)
500 kcal
daily deficit needed to lose approximately 1 lb per week
Understanding your metabolism
BMR vs TDEE: which number to use
BMR is the absolute minimum calories to survive. TDEE is what you actually need day-to-day. For weight management, use TDEE as your baseline: eat below it to lose weight, above it to gain. Never sustain a calorie intake below BMR — it risks muscle catabolism and metabolic slowdown over time.
Muscle raises your BMR
Muscle tissue is metabolically expensive — it burns roughly 6–10 kcal per pound per day at rest, compared to fat tissue at 2–3 kcal. Adding 5 lbs of lean muscle raises BMR by 30–50 kcal/day — not dramatic, but meaningful over years. Resistance training raises BMR both directly (muscle mass) and indirectly (post-exercise calorie burn lasting 24–72 hours).
Adjust every 5–10 lbs
As your weight changes, your BMR changes too. Recalculate every time you gain or lose 5–10 lbs to keep your calorie target accurate. Failing to update leads to a stall — your deficit shrinks as you get lighter, and without recalculation you unknowingly return to maintenance calories without realising it.
How the BMR Calculator Works
Formula
Male BMR = (10 × kg) + (6.25 × cm) − (5 × age) + 5\nFemale BMR = (10 × kg) + (6.25 × cm) − (5 × age) − 161This calculator uses the Mifflin-St Jeor equation (1990), the most widely validated BMR formula for adults. Enter weight in kilograms, height in centimetres, and age in years.
The BMR result is then multiplied by standard activity factors: ×1.2 (sedentary), ×1.55 (moderately active), and ×1.725 (very active) to estimate Total Daily Energy Expenditure at each level.