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Ideal Weight (by Target Body Fat) Calculator

Enter current weight, current body-fat percentage, and target body-fat percentage to estimate ideal weight via the lean-mass method.

Input Data

Weight
Current Bf
%
Target Bf
%

Results

63
50.4
7

At a glance:Enter current weight, current body-fat percentage, and target body-fat percentage to estimate ideal weight via the lean-mass method.

Formula

Lean mass = weight × (1 − current BF).

Ideal weight = lean mass ÷ (1 − target BF).

Weight to lose = current weight − ideal weight.

How to Use

  1. Enter current weight, current body-fat %, and target body-fat %.
  2. The calculator returns ideal weight, lean mass, and weight to lose.

FAQ

What is lean body mass?

Lean body mass is the part of weight left after subtracting fat — muscle, bone, water, organs, etc. It is not affected by how much fat you have, so it is a stable baseline for estimating ideal weight.

Why not use BMI for ideal weight?

BMI only uses height and weight and cannot tell muscle from fat. A muscular person may have a high BMI yet be healthy; the lean-mass method uses body fat as the basis and is closer to actual composition.

What is a reasonable target body-fat %?

Generally healthy men about 10–20%, women about 18–28%; athletes are lower. Setting it too low (e.g. men < 6%) is hard to maintain long term and may affect hormones — set a realistic range.

Does lean mass stay completely constant during fat loss?

Ideally you preserve it, but a too-large deficit or lack of protein/resistance training loses muscle. This tool assumes it is constant as an estimate; in practice re-measure body fat periodically to correct.

Is this tool useful when gaining muscle (body fat unchanged)?

If the goal is muscle gain with rising body fat, the formula still holds, but "ideal weight" shifts with target body fat. This tool is mainly for setting fat-loss goals; for muscle gain use lean-mass increase as the indicator.

Is it normal that the result differs a lot from BMI ideal weight?

Yes. For example, a muscular man may be flagged overweight by BMI, but the body-fat-based ideal weight can be higher. The two methods differ by design — choose by your health goal.

Related Tools

References

Content review: Calculatorism Science Team. Results are for reference only; please refer to the relevant authorities for the official figures.

Found a problem with the results?

If this calculator's result is wrong, or you have any question about the calculation logic, please let us know. You are viewing:Ideal Weight (by Target Body Fat) Calculator（/health/body-fat-ideal）。