Lean Body Mass Calculator
Estimate lean body mass and fat mass from height and weight.
Assumptions used in this calculation
- Formula: The Boer formula is a population estimate; individual muscle mass and frame size vary.
About this calculator
Scale weight alone doesn't tell you how much of it is muscle, bone and organs versus fat, and separating the two normally requires a body fat percentage measurement from calipers, a scan, or a tape-measure formula. This calculator skips that step: using the Boer formula, it estimates lean (fat-free) body mass directly from just height, weight and sex, applying sex-specific coefficients (0.407/0.267 for men, 0.252/0.473 for women) derived from population reference data. Fat mass is then found by subtracting lean mass from total weight. Because it needs no circumference measurements or body-fat percentage input, it's a fast way to get a lean-mass estimate when you only have a scale and a height measurement on hand, useful for tracking whether weight changes during a diet or training block are coming primarily from fat or from muscle. As with any population-based formula, individual results vary with actual frame size and muscularity.
Worked example
Male, 80 kg, 180 cm
Result: Lean body mass ≈ 61.4 kg
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