BMR Calculator
Basal metabolic rate from height, weight, age, and sex.
Inputs
This calculator gives a general estimate and isn't medical advice. It doesn't account for your individual health history — talk to a doctor before making decisions based on it.
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Formula
BMR = 10×weight(kg) + 6.25×height(cm) − 5×age − 161 (female) or + 5 (male)
The Mifflin-St Jeor equation estimates calories burned at complete rest — no digestion, movement, or exercise — using only body size, age, and sex.
Worked example
A 30-year-old man weighing 70 kg and standing 175 cm tall has a BMR of about 1,649 kcal/day — the baseline energy his body needs before any activity.
Where this can give the wrong answer
- BMR equations assume average body composition; two people with identical stats but very different muscle mass can have meaningfully different resting burn rates.
- Very low body weight or very young ages hit the input minimums — results below those thresholds are rejected rather than extrapolated.
- Mifflin-St Jeor is widely used but still an estimate; measured indirect calorimetry in a lab can differ by 10% or more.
FAQ
- BMR is calories at rest only. TDEE multiplies BMR by an activity factor to include walking, exercise, and daily movement. Use this calculator first, then plug the result into the TDEE calculator.