Katch-McArdle Calculator
Estimate BMR and daily calories with the Katch-McArdle formula, which uses lean body mass and your body-fat percentage. Free and private.
Independently verified for accuracy
Calculator by Toolsloft ↗- Lean body mass
- 68 kg
- BMR
- 1838.8 kcal/day
- Total daily calories
- 2850.14 kcal/day
The Katch-McArdle equation estimates your resting metabolic rate from lean body mass rather than total weight, so it tends to be more accurate if you know your body-fat percentage. Enter your weight and body-fat number to get your BMR and, with an activity level, your total daily calories.
How this is calculated
It computes lean body mass as weight times (1 minus body-fat fraction), then applies the Katch-McArdle formula BMR = 370 + 21.6 x lean mass in kg. Multiplying BMR by an activity factor (1.2 sedentary to 1.9 athlete) gives total daily energy expenditure.
How to use
- Enter your weight in kilograms.
- Enter your body-fat percentage (from a scan, calipers, or the body-fat calculator).
- Pick an activity level to see your BMR and total daily calories.
Examples
- 80 kg, 15% fat, moderate:
BMR 1,838.8, TDEE 2,850.14 kcal/day - 60 kg, 25% fat, light:
BMR 1,342, TDEE 1,845.25 kcal/day
FAQ
- When should I use Katch-McArdle instead of Mifflin-St Jeor?
- Use it when you know your body-fat percentage. Because it works from lean mass, it can be more accurate for very lean or very muscular people, where formulas based on total weight tend to over- or under-estimate.
- Where do I get my body-fat percentage?
- A DEXA scan, hydrostatic weighing, or calipers give the most reliable numbers. A tape estimate from the body-fat calculator works as a free starting point.
- What is the difference between BMR and TDEE here?
- BMR is the calories your body uses at complete rest. TDEE multiplies that by an activity factor to include daily movement and exercise, so it is closer to your real maintenance calories.