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BMR (Katch McArdle) Calculator

Work out bmr (katch mcardle) instantly with clear inputs, formula shown and shareable results.

About BMR (Katch McArdle) Calculator

Applies the Katch-McArdle equation, which predicts basal metabolic rate from lean body mass alone and so suits lean or muscular people best.

Formula

Katch-McArdle

BMR = 370 + 21.6 x lean body mass (kg), where lean mass = weight x (1 - body fat fraction)

Worked example

With the default values below, BMR (Katch McArdle) Calculator returns Basal metabolic rate of 1,838.8. Change any input above and every figure here is recalculated in your browser.

Inputs used

Weightaccepts 20–300 kg
80 kg
Body fataccepts 3–60
15

Results

Basal metabolic rate
1,838.8 kcal/day
Lean body mass
68.00 kg
Fat mass
12.00 kg
BMR per kilogram of lean mass
27.041 kcal/kg/day

Step by step

  1. 1Values used
  2. 2Katch-McArdle
  3. 3Basal metabolic rate= 1,838.8 kcal/day
  4. 4Lean body mass= 68.00 kg
  5. 5Fat mass= 12.00 kg
  6. 6BMR per kilogram of lean mass= 27.041 kcal/kg/day

Assumptions and limits

  • The result is derived only from the 2 inputs listed above. Anything not among them is not part of the calculation.
  • In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
  • Figures are rounded for display to 3 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.
  • Educational estimate only. Not a substitute for professional clinical judgement, and must not be used to make treatment or dosing decisions.
  • This is an estimate for general information and not professional medical advice. See the full disclaimer for the limits that apply to this kind of calculator.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Educational estimate only. Not a substitute for professional clinical judgement, and must not be used to make treatment or dosing decisions.

Frequently Asked Questions

When is this equation preferable?

When a reliable body composition measurement exists, especially in athletes where weight-based equations misfire.

Why does lean mass drive metabolic rate?

Fat tissue is metabolically quiet, so almost all resting energy expenditure comes from lean tissue and organs.

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