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Body Fat Calculator

Approximate body fat percentage from common measurement formulas and visualize lean vs fat mass.

Measurements

Body fat

16.9%

Fitness

Body composition

  • Fat mass: 11.8 kg
  • Lean mass: 58.2 kg
Estimate only — not medical adviceView details

Body fat estimates from formulas are approximations. For clinical accuracy, use professional measurement methods.

Body fat

16.9%

Fitness

How it works

Body-fat calculators approximate the percentage of your weight that is fat mass versus lean mass using circumference-based or other field methods—not a DEXA scan.

Enter the measurements your chosen method needs (for example Navy-style neck, waist, and hip circumferences, plus height and sex). The tool estimates body-fat percentage and can illustrate fat vs lean mass.

Tape methods are sensitive to posture, tape tension, and where you measure. Take repeats at the same time of day and average them for a more stable number.

Categories and “ideal” ranges vary by method and source. Use the percentage to track direction over months, not to obsess over a single decimal point.

Pair with BMI for a quick size screen, and with BMR/TDEE when you care about energy needs. None of these replace clinical body-composition testing when decisions are medical.

Frequently asked questions

How accurate is a tape-measure body-fat estimate?
It is an approximation. It can be useful for trends if you measure consistently, but it can disagree with DEXA, Bod Pod, or highly trained caliper testing.
Why do different formulas disagree?
Each method uses different inputs and was validated on different populations. Disagreement is normal; focus on one method over time.
Should I measure before or after meals?
Pick a routine and stick to it—many people prefer morning measurements before eating for consistency.
Is lower always better?
No. Extremely low body fat can be unhealthy. Context, performance, hormones, and medical guidance matter more than chasing the lowest percentage.

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