How accurate is the Deurenberg formula?
It is reasonable for general population screening but can over- or under-estimate for very muscular or very lean individuals.
Body Fat Calculator
Estimate your body fat percentage from height, weight, age, and sex using the widely cited Deurenberg equation.
Enter your measurements
Choose units, then enter age, sex, height, and weight.
About this calculator
How to use Body Fat Calculator, plus the formulas and logic behind the results.
Tool description
The Body Fat Calculator estimates body fat percentage using the Deurenberg formula, which combines BMI with age and sex. It is a quick screening estimate—not a replacement for DEXA or caliper testing.
How to use
- Select metric or US units.
- Enter your sex, age, height, and weight.
- Click Calculate to see estimated body fat % and BMI.
- Compare the result with typical ranges and consider professional testing if needed.
Formulas & reference
BMI = weight(kg) ÷ height(m)²BF% = 1.20 × BMI + 0.23 × age − 10.8 × sex − 5.4 (male sex = 1)Lean mass ≈ weight × (1 − BF% ÷ 100)
Typical adult body fat ranges
- Essential fat: men ~2–5%, women ~10–13%
- Athletes: men ~6–13%, women ~14–20%
- Fitness: men ~14–17%, women ~21–24%
- Average: men ~18–24%, women ~25–31%
Calculation logic
Height and weight are converted to metric, BMI is computed, then the Deurenberg equation returns an estimated body fat percentage. Results are clamped to a realistic 3–60% range.
Athletes, pregnant people, and older adults may get less accurate estimates. Circumference or DEXA methods can be more precise.
Body Fat Calculator FAQ
Common questions about this calculator and how to use the results.
Do I need to fast before using this?
No. This estimate uses height, weight, age, and sex only—not same-day hydration or meal timing.
Why does sex affect the result?
The formula uses a sex coefficient because average fat distribution differs between men and women at the same BMI.
Can I use this if I lift weights regularly?
Use caution. Higher muscle mass can lower BMI-based fat estimates. A direct body composition test may be better.
What units should I use?
Either metric (cm, kg) or US units (ft/in, lb). The calculator converts internally.
Is this a medical diagnosis?
No. It is an educational estimate. Talk to a clinician for health decisions.