Body Fat Calculator

Estimate your body fat percentage using the US Navy measurement method. Enter your measurements for instant results.

How to measure: Use a flexible tape. Neck — just below the larynx. Waist — narrowest point (women) or navel (men). Hips (women) — widest point.

Height (cm)

Neck (cm)

Waist (cm)

Hips (cm) women only

About This Tool

What it does

Estimates body fat percentage using the US Navy circumference method — a widely used formula requiring only a tape measure. Shows your result alongside healthy range guidance from the American Council on Exercise (ACE).

Who it's for

Anyone wanting a quick body composition estimate without specialist equipment. Popular with gym-goers, athletes and anyone tracking fitness progress. More meaningful than BMI alone as it distinguishes fat from muscle.

Your privacy

All calculations happen in your browser. No data is transmitted or stored anywhere.

What the body-fat estimate represents

The US Navy method uses circumference measurements and height to estimate body-fat percentage. It is inexpensive and repeatable, but it is still an indirect estimate rather than a clinical measurement.

Improve consistency

Measure at the same time of day and under similar conditions.
Keep the tape level and avoid pulling it too tightly.
Track the trend over time instead of reacting to one reading.

Body fat and BMI answer different questions

BMI relates weight to height, while a body-fat estimate attempts to separate fat from fat-free mass. Both can be useful screening references, and both can misrepresent individual health.

This calculator is not a diagnosis. Discuss health concerns or major weight changes with a qualified healthcare professional.

Method and international references

This circumference method is based on the US Navy body-composition approach. It is useful for repeatable self-tracking but is less precise than clinical assessment and should not be treated as a diagnosis.

Sources: US Navy Physical Readiness guides; World Health Organization: obesity and BMI; US CDC: BMI as a screening measure.

Helpful guides

Body fat percentage vs BMICompare the two measures, their strengths and their limitations.Read guide →

Frequently Asked Questions

How is body fat percentage calculated?

This calculator uses the US Navy circumference method using neck, waist and hip measurements. It is one of the most accessible methods that does not require specialist equipment such as calipers or DEXA scanning.

What is a healthy body fat percentage?

According to the American Council on Exercise (ACE): women — athletic 14-20%, fit 21-24%, acceptable 25-31%. Men — athletic 6-13%, fit 14-17%, acceptable 18-24%. Essential fat (minimum needed for health) is 10-13% for women and 2-5% for men.

How accurate is the Navy method?

Accuracy is approximately ±3-4% when measurements are taken correctly. Less accurate than DEXA scanning but far more accessible. For most consistent results measure first thing in the morning.

How do I measure correctly?

Use a flexible tape. Neck: just below the larynx. Waist: narrowest point (women) or navel level (men). Hips (women only): widest point. Stand relaxed and exhale before measuring.