Body composition estimator

See what your body-fat target could mean in numbers.

Estimate body composition, target weight, the approximate amount of fat to lose, and the mathematical scale of the task.

Your starting point and target

Enter a value from 50 to 250 kg.
Body-fat percentage is an estimate. Appearance varies between individuals. Choose the example that looks closest to your current condition.
Choose a lower body-fat target. The images are visual references only, not precise measurements.

Use the images as approximate visual references only. Body shape, muscle mass, age, genetics and fat distribution can affect appearance at any given body-fat percentage.

Estimated target weightβ€”
Estimated fat to loseβ€”
Target body fatβ€”

Current β†’ target

Current
β€”
Estimated body fatβ€”
Estimated fat massβ€”
Estimated lean massβ€”
β†’
Selected target
β€”
Target body fatβ€”
Estimated target fat massβ€”
Lean massβ€”
Estimated fat to lose
β€”

Lean mass is assumed to be maintained for this estimate. It is a modelling assumption, not a guarantee.

The numbers

Approx. energy in 1 kg fat~7,700 kcal
Approx. fat-energy equivalentβ€”

This is an educational modelling approximation. It is not an exact statement of human physiology or a guaranteed total calorie deficit.

Mathematical time estimates

~500 kcal/day gapβ€”β€”
~750 kcal/day gapβ€”β€”
~1,000 kcal/day gapβ€”β€”

Mathematical comparisons only. Real-world rates vary and are not perfectly linear. A larger gap is not automatically more appropriate.

Illustrative energy example β€” not a personal calorie prescription

Daily energy expenditure and supply

Estimated BMR
β€”
+
Activity
β€”
=
Theoretical TDEE
β€”

TDEE uses the same moderately active Γ—1.55 theoretical example as the static visual series. β€œActivity” is the illustrative difference between BMR and this activity-factor TDEE; it is not a measured NEAT/EAT breakdown.

Theoretical TDEE
β€”
βˆ’
Illustrative energy supply
β€”
=
Energy gap
~500 kcal/day

The energy-supply figure is an illustrative worked example, not a recommended personal calorie target. A sustained energy gap can encourage the body to draw on stored energy, including body fat.

Calculation basis

Target weight is estimated by holding current estimated lean mass constant. Fat-energy equivalent uses ~7,700 kcal/kg. BMR uses Katch-McArdle. TDEE uses a fixed moderately active Γ—1.55 example. Time estimates divide the fat-energy equivalent by the selected mathematical daily energy gaps.

Educational estimator for adult men. Not a diagnostic or clinical tool.
These figures are estimates, not guarantees or personal prescriptions. Body-fat assessment, BMR, TDEE, lean-mass retention and real-world rates of fat loss all involve uncertainty.