DefinitionBody fat percentage is the share of your total weight that is fat, a more direct measure of body composition than BMI.
What it means
Ways to estimate it, from most to least precise in everyday settings:
- DEXA scans, which also show lean mass and bone
- Bioimpedance scales and handheld devices, which vary with hydration
- Tape-measure methods like the US Navy formula
- Skinfold calipers, which depend on the tester's skill
Every method has error. The trend from the same method, under the same conditions, is more useful than any single reading.
Healthy ranges differ by sex and age. Women carry more essential fat than men, so the same number means different things for each.
If you want to track change, measure at the same time of day, with the same device, and under similar conditions, such as first thing in the morning before eating. Pick one method and stick with it.
Why it matters
Entering body fat lets the TDEE calculator switch to Katch-McArdle, which can be more accurate for lean or very muscular people.