How accurate is the Navy body fat formula?

It's pretty accurate for most people, studies show it's within 2–4% of DEXA scan results on average. That said, it works better for average body types and may be less accurate for very lean or very heavy people.

Can I use a body fat calculator to track fat loss?

Yes, and it really is one of the best ways to use it. Repeat the measurement every four to six weeks under the same conditions (same time of day, same measuring technique). Even small percentage drops mean something over months.

Is body fat percentage a better measure than BMI?

For many people, yes. BMI doesn’t even consider muscle mass. A regular weightlifter can have a high BMI, but very little body fat. A body fat percentage will give you a better idea of actual body composition.

Is CalciHub's Body Fat Calculator free?

Yes, completely free. No login, no subscription, just open the calculator, enter your measurements and get your result.

Body Fat Calculator

Estimate your body fat percentage using the Navy or BMI method

Measurements

Unit System

Method

Gender

Height (cm)

Neck circumference (cm)

Abdomen / Waist circumference (cm)

Weight (kg) (optional, for fat/lean mass)

Results

Enter your measurements and click Calculate

What is the Body Fat Calculator?

Body fat percentage gives you a clearer picture of your body composition by showing how much of your weight is fat. including muscle, bone, water, organs. It's a better health marker than BMI for a lot of people, especially athletes or anyone who lifts regularly. CalciHub's body fat calculator uses your measurements to estimate your fat percentage (%) and tell you whether it falls in an essential, athletic, fit, average, or obese range. No gym equipment or DEXA scan required. It only takes a few minutes and a measuring tape to get your results.

The Science Behind the Body Fat Calculator?

CalciHub uses the U.S. Navy body fat formula, which is based on circumference measurements.

For men: Body fat % = 86.010 × log10(waist − neck) − 70.041 × log10(height) + 36.76

For women: Body fat % = 163.205 × log10(waist + hip − neck) − 97.684 × log10(height) − 78.387

waist = circumference at the narrowest point (men) or navel (women), in cm or inches neck = circumference at the narrowest point of the neck hip = circumference at the widest point (women only) height = standing height in cm or inches

How to Use CalciHub's Body Fat Calculator.

1. Choose your preferred unit system – select Metric or Imperial.

2. Select a calculation method – choose the Navy or BMI method.

3. Select your gender – This helps improve the accuracy of your estimate.

4. Enter your height – Add your current height.

5. Measure and enter your neck circumference

6. Measure and enter your waist circumference

7. Add your weight – This can provide additional body composition insights.

8. Women only: measure and enter your hip circumference.

9. Click "Calculate" to get your estimated body fat percentage and category." Your body fat estimate will be ready within a few seconds.

Tip: Take measurements in the morning before eating. Measure each spot twice and average them; consistency matters more than precision.

How It Works with a Real Example

Emma is 5'4" (162.5 cm), with a waist of 30 inches, a neck of 13 inches, and hips of 38 inches. She enters her numbers into CalciHub's body fat calculator.

Height: 5'4" | Waist: 30" | Neck: 13" | Hips: 38"

Result: approximately 26% body fat, which falls in the "average" range for women.

Emma has been strength training for six months and expected a lower number. Her trainer reminds her that scale weight and fat percentage don't always move together. She's likely been building muscle while gradually losing body fat. The calculator gives her a baseline to track from here.

Frequently Asked Questions

A healthy body fat percentage for women is usually between 20–32%. For men, it's about 10–20%. Athletes often sit lower, 14–20% for women and 6–13% for men. What's 'healthy' depends on your age, sex, and fitness goals.

See all Health & Fitness →