BMR Calculator
Calculate your basal metabolic rate with Mifflin-St Jeor or Katch-McArdle equations.
Last updated: August 2026
BMR
1,618 kcal
Sedentary need
1,941 kcal
x1.2 — mostly desk work
Moderate need
2,507 kcal
x1.55 — 3-5 workouts/week
BMR is calories at complete rest. Multiply by an activity factor (1.2–1.9) for total daily needs.
How it works
Mifflin-St Jeor: male 10W + 6.25H − 5A + 5; female 10W + 6.25H − 5A − 161. Katch-McArdle: 370 + 21.6 × lean mass.
Example: male 70 kg / 170 cm / 30 yr → BMR 1,618 kcal.
Frequently Asked Questions
What is BMR?
BMR (basal metabolic rate) is the energy your body burns at complete rest just to stay alive — breathing, heartbeat, body temperature. It is usually 60–70% of your total daily burn.
Which BMR formula is most accurate?
Mifflin-St Jeor is considered the most accurate for the general adult population. Katch-McArdle is better for athletes because it uses lean body mass directly.
How do I turn BMR into daily calories?
Multiply BMR by an activity factor: 1.2 for sedentary, 1.375 light, 1.55 moderate, 1.725 very active, 1.9 extra active. That gives your maintenance calories.
Does BMR decrease with age?
Yes. Muscle mass typically declines with age, and BMR drops by roughly 2% per decade after adulthood. Strength training helps slow that decline.