BMR Calculator for Men — Male Metabolic Rate

The male version of the Mifflin-St Jeor equation is the standard equation with + 5 on the end. That is the entire difference — there is no separate men’s formula. Enter age, weight and height:

The male formula, worked out

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

The equation runs on metric units, so convert before you substitute. A 35-year-old man at 180 lb and 5 ft 10 in: 180 ÷ 2.205 = 81.6 kg, and 70 in × 2.54 = 177.8 cm.

10 × 81.6 + 6.25 × 177.8 − 5 × 35 + 5 = 816 + 1,111 − 175 + 5 = 1,757 kcal/day

A heavier, taller man — 220 lb and 6 ft 2 in at the same age, which is 99.8 kg and 188.0 cm — comes out at 998 + 1,175 − 175 + 5 = 2,003 kcal/day. Roughly 250 kcal of resting difference for 40 lb and four inches. If the conversion step is where you would rather not risk a slip, the pounds to kg and feet and inches to meters pages handle it.

The 166 kcal that separates the sexes

The familiar “+5 for men, −161 for women” hides how small the difference really is. In the regression Mifflin and colleagues actually published, sex enters once, as a single term:

REE = 9.99 × weight + 6.25 × height − 4.92 × age + 166 × sex − 161, with sex coded 1 for males and 0 for females.

So the whole male-female gap in this equation is 166 kcal a day, flat, independent of size. And it is a proxy, not a cause. The 2023 Dietary Reference Intakes are explicit that once body composition is controlled for, sex shows minimal independent effect on resting metabolic rate. What the constant is really encoding is that men in the fitting sample carried more fat-free mass than the women did, at the same recorded weight.

Which leads to the equation’s real blind spot.

What the equation cannot see about you

Fat-free mass accounts for 60 to 80% of the variation in resting energy expenditure between individuals; body weight alone explains only about half. The equation takes the half it can measure and approximates the rest with a sex constant.

The consequence is concrete. Two men, both 180 lb, both 5 ft 10 in, both 35 — one carrying considerable muscle and 12% body fat, the other sedentary at 28% — get the same 1,757 kcal from this page. Their measured resting rates would differ. Body composition, not the calculator, is what separates them, and BMI vs body fat percentage explains why the scale cannot tell you which case you are.

The age term is a straight line through a curve

The formula charges you 5 kcal per year, every year, from 19 to 78. The measured trajectory is not that shape. Size-adjusted energy expenditure declines through adolescence, reaches adult level around age 20, stays stable through about 60, and only then falls as fat-free mass and organ metabolism decline.

In other words, a man’s resting rate does not begin a steady annual descent at 30. What tends to descend at 30 is his lean mass and his daily movement, and the equation’s age coefficient is absorbing both. That is a hopeful reading rather than a pessimistic one, because both of those respond to training. The BMR calculator for seniors covers where the curve actually bends.

From resting to a food plan

The number above is a floor, not a budget — it excludes every step you take. Multiply it by an activity factor to reach total daily expenditure before planning anything; the BMR vs TDEE page shows how large that step is. If you want to compare equations, the older Harris-Benedict calculator reads about 5% higher for the same man, and the main BMR calculator explains where these numbers come from.

This content is informational and does not replace evaluation by a physician or registered dietitian.