How to Calculate BMR

Your basal metabolic rate is the energy you'd burn lying still all day. Here's the equation dietitians use, a worked example, and what to do with the result.

1. The Mifflin–St Jeor equation

Men: BMR = 10 × weight(kg) + 6.25 × height(cm) − 5 × age + 5

Women: BMR = 10 × weight(kg) + 6.25 × height(cm) − 5 × age − 161

2. A worked example

A 30-year-old man, 80 kg, 178 cm:

10 × 80 = 800
6.25 × 178 = 1,112.5
5 × 30 = 150
800 + 1,112.5 − 150 + 5 = 1,767.5 ≈ 1,768 kcal

Prefer to skip the arithmetic? The BMR calculator does it instantly.

3. Turn BMR into a daily target

Multiply BMR by an activity factor — 1.2 sedentary, 1.375 light, 1.55 moderate, 1.725 high, 1.9 very high — to get maintenance calories (TDEE). Our example man at 1.55 needs about 2,740 kcal to hold his weight. Then subtract for fat loss or add for muscle gain with the deficit calculator.

4. How accurate is it?

Mifflin–St Jeor predicts resting energy within about 10% for most healthy adults. It's less accurate at the extremes of body composition, because it doesn't know your muscle mass. Treat the output as a starting estimate and correct it against your own weight trend over 2–3 weeks.