Body Recomposition Estimate Calculator

Work out body recomposition estimate instantly with clear inputs, formula shown and shareable results.

About Body Recomposition Estimate Calculator

Recomposition changes what the body is made of more than what it weighs. An 80 kg person at 24% fat holding 60.8 kg lean who gains 1.5 kg of muscle and reaches 18% fat would weigh 75.9 kg - only 4 kg less on the scale, despite losing 7.5 kg of fat. This is why scale weight alone hides real progress.

Formulas

Lean mass after

lean = current lean + muscle gained

Target weight

target = lean / (1 - target body fat)

Worked example

With the default values below, Body Recomposition Estimate Calculator returns Weight At The Target Body Fat of 75.98. Change any input above and every figure here is recalculated in your browser.

Inputs used

Body weightminimum 0 kg: 80 kg
Current body fataccepts 1–70 %: 24 %
Target body fataccepts 1–70 %: 18 %
Muscle expected to be gainedminimum 0 kg: 1.5 kg

Results

Weight At The Target Body Fat: 75.98 kg
Fat Mass To Lose: 5.52 kg
Lean Mass After Recomposition: 62.30 kg
Net Change On The Scale: -4.02 kg

Step by step

1Values used
2Lean mass after
3Target weight
4Weight At The Target Body Fat= 75.98 kg
5Fat Mass To Lose= 5.52 kg
6Lean Mass After Recomposition= 62.30 kg
7Net Change On The Scale= -4.02 kg

Assumptions and limits

The result is derived only from the 4 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 2 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.
These figures are population-average estimates, not a medical assessment or diagnosis. Body composition equations carry errors of several percentage points, and healthy ranges vary with age, ethnicity, muscularity and medical history. Discuss weight or body composition goals with a qualified clinician or dietitian.
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.

These figures are population-average estimates, not a medical assessment or diagnosis. Body composition equations carry errors of several percentage points, and healthy ranges vary with age, ethnicity, muscularity and medical history. Discuss weight or body composition goals with a qualified clinician or dietitian.

Frequently Asked Questions

Can I really gain muscle in a deficit?

Yes, in beginners, those returning from a break and people with higher body fat, provided protein and resistance training are adequate. It is slow for trained lifters.

Why does the scale barely move?

Because fat lost and muscle gained partly cancel. Track waist circumference and photographs alongside weight.