Body fat calculator
Estimate your body fat percentage in seconds with the US Navy method — the most common tape-measure approach. You just measure your neck and waist (and hip for women) plus your height. We give you the percentage, your category and, if you add weight, your fat and lean mass.
Your estimated body fat
16.9%
Fitness
Try Renzy freeRenzy tracks your progress: weight, measurements and a body scan to watch your fat drop month by month.
US Navy tape-measure estimate. Margin of error ±3-4% vs DEXA. Not a medical diagnosis.
How is body fat calculated?
The US Navy method estimates body fat from body circumferences and height, using a formula validated by the US Navy. Men use neck and waist; women also add the hip, because fat distribution differs. It carries a ±3-4% margin vs DEXA (the gold standard) but is very useful for tracking over time if you always measure the same way: fasted, tape not too tight, same landmarks. With your weight we also split fat vs lean mass in kg.
FAQ
What body fat percentage is healthy?
It depends on sex. For men, a fitness range is ~14-17% and healthy average 18-24%; for women, fitness 21-24% and average 25-31%. Below essential fat (≈5% men, ≈13% women) there are hormonal risks.
How do I measure waist and neck correctly?
Neck: just below the larynx, tape angled slightly down. Waist: men at navel level; women at the narrowest point. No squeezing, normal breathing, ideally fasted in the morning.
Is the US Navy method reliable?
For tracking progress, yes — consistent and repeatable. For an exact absolute figure, DEXA is more precise but pricier. What matters is measuring the same way and watching the trend.
How much fat can I lose per month?
A healthy pace is ~0.5-1% body fat per month while keeping muscle, with a moderate deficit and enough protein.