BMR Calculator
Enter valid age, height, and weight (and body fat % if using Katch-McArdle).
This is the energy your body burns just staying alive (breathing, circulation, cell repair) — before any activity. Most people multiply this by an activity factor to get total daily calorie needs; see our TDEE Calculator for that next step.
Free BMR calculator with a choice of three formulas — Mifflin-St Jeor, Harris-Benedict, and Katch-McArdle for people who know their body fat percentage — not just the one formula most calculators default to.
How it works
- Enter your sex, age, height, and weight
- Pick a formula — Mifflin-St Jeor is the most broadly accurate default
- See your basal metabolic rate: calories burned at complete rest
Frequently asked questions
Which formula should I use?
Mifflin-St Jeor is considered the most accurate for most people. Katch-McArdle can be more accurate if you know your body fat percentage (from a DEXA scan or reliable body fat test), since it accounts for lean mass directly rather than estimating from height and weight alone.
Is BMR the same as the calories I should eat?
No — BMR is calories burned at complete rest, before any movement. To get your actual daily calorie needs, multiply BMR by an activity factor, or use our TDEE Calculator, which does that step for you.
Related tools
From the blog
Update history
- 2026-09-03 Age, height, and weight are now sliders instead of number fields, and the sex toggle shows an icon for each option.
- 2026-09-01 Added: a cover image — used as the card thumbnail, social share image, and blog title image.
- 2026-09-01 Launched: BMR calculator with a choice of three formulas (Mifflin-St Jeor, Harris-Benedict, Katch-McArdle), unlike most calculators that only offer one. Entirely client-side.