Plain-language meaning
Body fat percentage estimates how much of total body weight is fat mass. The rest is lean mass, which includes muscle, bone, organs, water and other tissue.
Example
If a person weighs 80 kg and body fat is estimated at 20%, the estimated fat mass is 16 kg and the estimated lean mass is 64 kg.
How estimates differ
Body fat calculators may use circumference measurements, skinfolds, bioelectrical impedance, imaging methods or population formulas. These methods can give different results for the same person.
Limitations
A calculator estimate is not a medical assessment. Hydration, measurement technique, age, sex, training status and the chosen formula can all change the result. For clinical or athletic decisions, use a validated measurement method and qualified guidance.
What to check
- Use the same measurement method when tracking change over time.
- Measure waist, neck, hip or skinfold inputs consistently if the method requires them.
- Do not compare results from different methods as if they were identical.
FAQ
Is body fat percentage better than BMI?
It answers a different question. BMI uses height and weight only; body fat percentage tries to estimate body composition.
Can a calculator measure body fat directly?
No. A calculator estimates body fat from the inputs and formula provided.