Body Fat Calculator
Last updated: June 2026 · Free · No sign-up required
Enter values above and click Calculate to see your result instantly.
Quick reference
| ACE category | Men | Women |
|---|---|---|
| Essential | 2–5% | 10–13% |
| Athletes | 6–13% | 14–20% |
| Fitness | 14–17% | 21–24% |
| Average | 18–24% | 25–31% |
| Obesity | 25%+ | 32%+ |
monitor_weight A starting point, not a diagnosis
This calculator gives you the same number a clinician would compute by hand from your inputs. It is informational, never a substitute for a doctor. If a result surprises you, write it down and discuss it at your next appointment — that conversation is the goal, not a verdict from a webpage.
science Built from peer-reviewed formulas
Every health calculator on CalcaTools uses an equation from the WHO, NIH, ACOG, CDC, or a published peer-reviewed paper. The exact citation is in the "Formula & methodology" section. We re-check sources quarterly and update the page when guidance changes — the "Last reviewed" date is at the top.
volunteer_activism Designed for real people
Health calculations only help if you can actually use them. We use plain-English labels (no jargon), accept both metric and US units, and show what a "normal" range looks like alongside your result — so you understand what the number means, not just what it is.
lock Private by design
Your weight, height, age, pregnancy details, and any other health input never leave your browser. Calculations run client-side; nothing is logged or stored on our side. We don't want your medical data — we just want the formula to work for you.
Interpretation guide
| Measurement tip | Why it matters |
|---|---|
| Measure relaxed | Flexing changes circumference |
| Use same tape position | Consistency beats one-off precision |
| Compare trends | Home methods are estimates |
lightbulb A real-world example — Navy method on a 5'10" man, 180 lb, 34" waist
Result: Body fat ≈ 17.5%. This is the lower end of "average" for men aged 30–39 (acceptable range 18–24%, fit 11–17%).
What this means: The Navy method is accurate to within ±3% for most people — fine for tracking trends but never substitute it for a DEXA scan if you need clinical accuracy. Watch the waist measurement: a 1-inch increase typically adds ~3% to the body-fat reading, so measure consistently (morning, no breath held, tape level with the navel).
Formula & methodology
Formula: US Navy circumference method using waist, neck, height and hip where applicable
The Navy method estimates body-fat percentage from body circumferences. It is convenient for tracking trends but less precise than DEXA, BodPod or clinician-grade assessment.
Authoritative source: U.S. Navy circumference method