Calculator Servicescalculatorservices.com
Health

Lean Body Mass Calculator

Estimate lean body mass using the Boer formula. Free online Lean Body Mass Calculator for health — instant, accurate results, mobile-friendly, no signup needed.

Navy method uses waist/neck/height (and hip for women).
LBM (kg)
56.015

Derivation

  1. ├── 01Givenw = 70, h = 175, sex = male
  2. ├── 02Formula{let t=e.w,a=e.h;return"male"===e.sex?.407 × t+.267 × a-19.2:.252 × t+.473 × a-48.3}
  3. ├── 03Substitute{let t=e.70,a=e.175;return"male"===e.'male'?.407 × t+.267 × a-19.2:.252 × t+.473 × a-48.3}
  4. └── 04Compute LBM (kg)56.015
Did you know?

The US Navy body-fat equation (1984) uses only neck, waist (and hip for women) — developed so recruiters could assess fitness without specialist equipment.

§01What is

Understanding the Lean Body Mass Calculator

The Lean Body Mass Calculator computes LBM (kg) from 3 inputs: weight (kg), height (cm), sex. Estimate lean body mass using the Boer formula.

Health metrics give us objective checkpoints against a body that can feel unreliable. Used alongside professional guidance — not in place of it — these numbers help you track progress and spot trends that matter. The Lean Body Mass Calculator sits in that toolkit — it estimate lean body mass using the Boer formula. Enter your numbers above and the result updates instantly; every step of the math is shown in the Derivation panel so you can see exactly how the answer was reached.

§02The Formula

How it’s calculated

{let t=e.w,a=e.h;return"male"===e.sex?.407 × t+.267 × a-19.2:.252 × t+.473 × a-48.3}

Where

w
Weight (kg)
h
Height (cm)
sex
Sex — one of: male, female
§03Practical Example

Step-by-step walkthrough

Scenario

Apply the formula to a realistic set of inputs: Weight (kg) = 70, Height (cm) = 175, Sex = male.

  1. 01Start by noting the input — Weight (kg): 70.
  2. 02Start by noting the input — Height (cm): 175.
  3. 03Start by noting the input — Sex: male (a category, not a number).
  4. 04Substitute these values into the formula: {let t=e.w,a=e.h;return"male"===e.sex?.407 × t+.267 × a-19.2:.252 × t+.473 × a-48.3}
  5. 05Compute LBM (kg): the calculator returns 56.015.
  6. 06Cross-check the answer by opening the Derivation panel above — every line of math is shown so you can follow the computation end-to-end.
§04Variants

Common Lean Body Mass Problems

The formula gets rearranged depending on which variable you need. Here are the patterns you’ll run into in the real world — find the one that matches your problem and follow the worked steps.

01 · PATTERN

Weight (kg) halved

w = 35 (from 70)

Keep every other input at its default and halve the weight (kg). See how lbm (kg) responds.

  1. 01New Weight (kg): 35
  2. 02Baseline LBM (kg): 56.015
  3. 03New LBM (kg): 41.77
  4. 04LBM (kg) decreases by 25.4% → use this sensitivity to plan for real-world variation.
02 · PATTERN

Weight (kg) doubled

w = 140 (from 70)

Keep every other input at its default and double the weight (kg). See how lbm (kg) responds.

  1. 01New Weight (kg): 140
  2. 02Baseline LBM (kg): 56.015
  3. 03New LBM (kg): 84.505
  4. 04LBM (kg) increases by 50.9% → use this sensitivity to plan for real-world variation.
03 · PATTERN

Height (cm) halved

h = 87.5 (from 175)

Keep every other input at its default and halve the height (cm). See how lbm (kg) responds.

  1. 01New Height (cm): 87.5
  2. 02Baseline LBM (kg): 56.015
  3. 03New LBM (kg): 32.6525
  4. 04LBM (kg) decreases by 41.7% → use this sensitivity to plan for real-world variation.
04 · PATTERN

Height (cm) doubled

h = 350 (from 175)

Keep every other input at its default and double the height (cm). See how lbm (kg) responds.

  1. 01New Height (cm): 350
  2. 02Baseline LBM (kg): 56.015
  3. 03New LBM (kg): 102.74
  4. 04LBM (kg) increases by 83.4% → use this sensitivity to plan for real-world variation.
§05FAQ

Frequently asked questions

Yes. The calculator implements the standard formula as documented and returns exact floating-point results. No approximations are used unless noted in the formula.
Your feedback

How useful was this calculator?

Your ratings stay in your browser — they help us learn which tools people actually rely on.

Rate it
Was this helpful?