Home › Guides › BMR (Basal Metabolic Rate)
Health · 6 min read · Last updated September 2026
Worked example — 80 kg, 180 cm, 30-year-old male: 10 × 80 = 800; 6.25 × 180 = 1,125; 5 × 30 = 150. So 800 + 1,125 − 150 + 5 = 1,780 kcal/day.
| Activity level | Multiplier | Same man's TDEE |
|---|---|---|
| Sedentary (desk job) | × 1.2 | 2,136 kcal |
| Lightly active | × 1.375 | 2,448 kcal |
| Moderately active | × 1.55 | 2,759 kcal |
| Very active | × 1.725 | 3,071 kcal |
The multiplier you pick moves the answer more than any formula choice — a sedentary vs very-active pick spans 900+ kcal. Calibrate honestly: most desk workers are 1.2–1.375 even with gym visits.
The older Harris-Benedict equation gives 1,854 kcal for the same man — 74 kcal higher than Mifflin. Neither is "wrong": both are population regressions with real scatter (roughly ±200 kcal for any individual). Mifflin is preferred today because it tracks measured values somewhat better in modern populations.
The standard Mifflin-St Jeor formula: 10 × weight in kg + 6.25 × height in cm − 5 × age, plus 5 for men or minus 161 for women. For an 80 kg, 180 cm, 30-year-old man that is 1,780 kcal/day.
BMR declines roughly 5 kcal per year of age in the formula (the −5 × age term). Typical adult values fall between about 1,200 and 1,900 kcal/day depending on size, sex and age — there is no single "good" number.
No. BMR is your burn at complete rest; total daily needs (BMR × activity factor) are the relevant baseline. Eating at or below BMR while active creates an unnecessarily aggressive deficit for most people.
Different equations (Mifflin vs Harris-Benedict) and different activity multipliers. The multiplier choice usually moves the total more than the equation does — pick your activity level honestly.
Multiply it by an activity factor to get your daily burn, then set your intake against that number. The ideal weight guide covers what a sensible target weight looks like, and the BMI guide explains the screening number most people pair with BMR.