Body Fat % + Lean Body Mass (LBM)

New here? Start in order: BMR/TDEE → Macros → Body Fat % / LBM → 1RM.

Estimate body fat % using the US Navy tape method. Then calculate fat mass and lean body mass (LBM). Best results come from consistent measuring (same time of day, relaxed abdomen).

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Tape Measurements
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Tip: measure 2–3 times and use the average. Keep the tape snug but not compressing skin.

Body Fat Percentage & Lean Body Mass (LBM) Calculator

This tool estimates your body fat percentage and lean body mass (LBM). Lean body mass is your bodyweight minus fat mass — a useful reference for tracking progress and setting nutrition targets.

What these numbers mean

  • Body fat %: the portion of your bodyweight that is fat.
  • Lean Body Mass (LBM): everything else — muscle, bone, organs, water, and glycogen.

How to use it

  1. Enter your measurements as accurately as possible.
  2. Click Calculate to estimate body fat % and LBM.
  3. Track changes over time using consistent measurement conditions.

Accuracy notes

Body fat estimates have error. The number is most useful when you measure consistently and track the trend over time (same tape placement, same time of day, similar hydration).

How to apply this

  • Use LBM as a reference when setting protein targets and comparing progress photos.
  • Combine this estimate with waist measurements, strength performance, and weekly scale averages.

Note: Estimates for informational purposes only, not medical advice.