Nutrition
As of 2026-04-24
How BMR Calculator works
Methodology for the BMR Calculator: formulas, coefficients, data sources, assumptions, and known limitations.
Scope
Computes Basal Metabolic Rate using the Mifflin-St Jeor equation — the calorie cost of staying alive at rest, which is the largest component of TDEE for most people.
Formula
BMR (men) = 10*weight_kg + 6.25*height_cm - 5*age + 5. BMR (women) same minus 166 instead of +5.
Coefficients
| Parameter | Value | Note |
|---|---|---|
| Weight coefficient | 10 kcal/kg | |
| Height coefficient | 6.25 kcal/cm | |
| Age coefficient | -5 kcal/year | |
| Sex constant | +5 (M) / -161 (F) |
Data sources
- Mifflin MD, St Jeor ST, Hill LA, et al. A new predictive equation for resting energy expenditure in healthy individuals. Am J Clin Nutr. 1990;51(2):241-247. — PMID 2305711.
- 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. — PMID 15883556. Meta-analysis validating Mifflin-St Jeor as the most accurate predictor.
Assumptions
- Subject is awake, fasted, thermoneutral, and resting.
Approximation range
RMSE vs indirect calorimetry in healthy non-obese adults: 150–200 kcal/day.
Limitations
- Systematically under-predicts for people with high lean mass; Katch-McArdle using LBM is more accurate there.
- Over-predicts for elderly and severely obese populations.
Reproducibility
Female, 65 kg, 165 cm, 35 yrs: BMR = 10*65 + 6.25*165 - 5*35 - 161 = 1345 kcal.
Change log
- 2026-04-24: methodology page first published.
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