The free Body Fat Percentage Calculator
Free body fat percentage calculator using the US Navy circumference method. Enter height, neck, waist (and hip for women).
- Free to use
- No signup
- Nothing to install
- Runs in your browser
Illustration. Open the tool for the real thing.
See it in action
Sample input: Height = 178; Neck circumference = 38; Waist circumference = 86; Hip circumference (women only) = 96
What is the Body Fat Percentage Calculator?
Body Mass Index does not distinguish between fat and muscle, which is why the US Navy developed a circumference-based method that estimates body fat percentage from a few tape-measure readings: height, neck and waist for men, plus hip for women. This calculator applies that formula and shows both the estimated body fat percentage and which category it falls into, from essential fat through athletic, fitness, average and obese ranges.
It is not as accurate as clinical methods like DEXA scans or hydrostatic weighing, but it is a free, private and reasonably reliable way to track trends over time using nothing more than a tape measure. Take the same measurements the same way each time for the most meaningful comparisons.
3 steps to your result
Open the tool and follow along. Nothing to install.
What you get
The circumference method used in military fitness testing.
Essential fat, athletic, fitness, average or obese range.
Enter measurements in cm/kg or inches/pounds.
Nothing is uploaded; the result appears as you type.
AZRS tools are free to open and use.
It opens in your browser, so there is nothing to download.
Used for
Pick one to see how it fits.
Anyone tracking fitness progress
A free way to estimate body composition without special equipment.
Try it freeAnyone starting a fitness plan
Get a starting-point estimate before a program begins.
Try it freeHow it compares
A plain look at this tool next to the usual alternative.
| This calculator | Desktop software | |
|---|---|---|
| Install | Nothing to install | Usually an app or program to install |
| Account | No signup | Depends on the product |
| Cost | Free to use | Free or paid, depends on the product |
| Where it runs | In your browser tab | On your computer |
Questions people ask
How accurate is the Navy method?
It is generally within a few percentage points of more precise methods like DEXA for most people, making it useful for tracking trends rather than an exact clinical reading.
What is a healthy body fat percentage?
Roughly 10–20% for men and 18–28% for women is often cited as a healthy range, though it varies with age and goals.
Do I need special equipment?
Just a flexible tape measure and a way to measure your height.
Why does the formula need hip measurement for women but not men?
Body fat distribution differs by sex, and the Navy formula's regression was developed separately for men and women to improve accuracy.
Is this the same as BMI?
No. BMI only uses height and weight; this method estimates actual body composition from circumference measurements.
More free tools
Related to the Body Fat Percentage Calculator.
Try the Body Fat Percentage Calculator now
Estimate body fat percentage using the US Navy circumference method. Free to use.
Try it free