Body Fat Calculator
US Navy method body fat from tape measurements.
Enter your values
Choose one of: Male, Female.
Enter the height in in.
Enter the neck circumference in in.
Enter the waist at navel in in.
Enter the hip (women only) in in.
Enter the weight in lb.
Results update instantly as you type — no submit needed. Your values are remembered on this device, and the shareable link reopens the calculator with exactly these numbers.
- Body fat
- 18%
- Category
- Fitness
- Fat mass
- 30.5 lb
- Lean mass
- 139.5 lb
Quick answer
The US Navy method estimates body fat from the log of neck, waist and hip circumferences relative to height, accurate to about ±3%.
At a glance
| What it does | US Navy method body fat from tape measurements. |
|---|---|
| Category | Health |
| Inputs needed | Sex, Height, Neck circumference, Waist at navel, Hip (women only), Weight |
| Main output | Body fat |
| Cost | Free — no sign-up, no download |
How to use the Body Fat Calculator
- 1Measure neck, waist and (for women) hips with a tape.
- 2Enter height and weight.
- 3Read the estimated body fat percentage.
Inputs explained
- Sex
- Choose one of: Male, Female.
- Height(in)
- Enter the height in in.
- Neck circumference(in)
- Enter the neck circumference in in.
- Waist at navel(in)
- Enter the waist at navel in in.
- Hip (women only)(in)
- Enter the hip (women only) in in.
- Weight(lb)
- Enter the weight in lb.
Worked example
Using the values the calculator loads with:
Inputs
- SexMale
- Height69 in
- Neck circumference15 in
- Waist at navel34 in
- Hip (women only)38 in
- Weight170 lb
Results
- Body fat18%
- CategoryFitness
- Fat mass30.5 lb
- Lean mass139.5 lb
Frequently asked questions
How accurate is the tape method?
Within about 3% of a DEXA scan for most people, and consistent enough to track change over time.
Where do I measure the waist?
At the navel for men, at the narrowest point for women, with the tape snug but not compressing skin.
What do I need to enter into the Body Fat Calculator?
Just 6 values: sex, height, neck circumference, waist at navel, hip (women only), weight. Every field starts with a realistic example, so you can change one number at a time and watch the result update instantly.
How does the Body Fat Calculator work out the answer?
The US Navy method estimates body fat from the log of neck, waist and hip circumferences relative to height, accurate to about ±3%. The working is shown step by step so you can verify the result by hand.
Is the Body Fat Calculator free, and do I need an account?
It is completely free with no sign-up, no download and no usage limit. Everything is calculated in your browser, so the numbers you type never leave your device.
Results are estimates for general information. For medical, legal, structural or financial decisions, confirm with a qualified professional.