Body Fat Percentage Calculator
Calculate your body fat percentage using the Navy method or BMI method. Track your fitness progress.
About this calculator
Enter your height, weight, waist and neck, and add your hips if you are a woman, and this calculator estimates your body fat percentage with the Navy method. It returns your body fat, fat mass and lean body mass.
It is a lighter version of the full body fat calculator, built for a quick check. Use it to see roughly where you stand and then to track change as you train and eat differently.
How to use it
- Choose Gender.
- Enter Height, Weight, Waist, Neck and, for women, Hip.
- Press Calculate Body Fat.
Navy formula
The US Navy method estimates body fat from tape measurements. Men: BF% = 495 ÷ (1.0324 − 0.19077 × log₁₀(waist − neck) + 0.15456 × log₁₀(height)) − 450. Women: BF% = 495 ÷ (1.29579 − 0.35004 × log₁₀(waist + hip − neck) + 0.22100 × log₁₀(height)) − 450, with all measurements in centimetres. Fat mass is body weight times BF%, and lean mass is the remainder.
Worked example
Man, 170 cm, 75 kg, waist 85 cm, neck 38 cm
| Body fat | 17.8% (Fit) |
| Fat mass | 13.3 kg |
| Lean body mass | 61.7 kg |
If your waist shrinks by 3 cm and your neck and weight stay the same, your estimated body fat falls by about 3 percentage points.
This tool gives general information, not medical advice. Talk to a doctor or dietitian before making changes to your diet, exercise or medication.
Tips and common mistakes
- Measure the waist at the same spot every time.
- A shrinking waist with a steady weight usually means fat loss and muscle gain.
- Weight alone can mislead. Use body fat to judge progress.
- Retake the measurement before you decide the result is wrong.
- See a professional if you want a clinical assessment.
Frequently asked questions
What is the Navy body fat method?
A formula developed by the US Navy that estimates body fat from height, waist, neck and, for women, hip circumference.
What is a normal body fat percentage?
About 14 to 24% for men and 21 to 31% for women is considered acceptable to average.
Why is my result different from a scale reading?
Smart scales use electrical impedance, which varies with hydration.
How can I reduce body fat?
A modest calorie deficit, high protein and regular strength training.
Does age matter?
Healthy ranges rise slightly with age.
Is this a medical test?
No, it is a screening estimate.