How accurate is the Navy body fat method?

The Navy method is reasonably accurate (within 3-4%) for most people and much better than BMI alone. However, it's less accurate than DEXA scans or hydrostatic weighing.

What's a healthy body fat percentage?

For men: 10-20% is athletic/fit, 21-25% is average. For women: 18-25% is athletic/fit, 26-31% is average. Essential fat is ~3% for men and ~12% for women.

Can I spot reduce body fat?

No, you can't target fat loss from specific areas. Fat loss occurs throughout the body based on genetics. Focus on overall fat loss through diet and exercise.

How long does it take to lose body fat?

Safe fat loss is 0.5-1% of body weight per week. For someone at 25% body fat wanting to reach 20%, this might take 2-4 months depending on starting weight.

My waist shrank from 92 cm to 85 cm (man, 178 cm, 40 cm neck) — how much body fat did I lose?

At 92 cm: 92 − 40 = 52 gives 495 / 1.0529 − 450 = 20.1% (Average). At 85 cm: 85 − 40 = 45 gives 495 / 1.0648 − 450 = 14.9% (Fitness). That 7 cm waist drop equals about 5.2 percentage points of body fat.

I am a 180 cm man with a 42 cm neck and 102 cm waist — what is my body fat?

Waist minus neck is 102 − 42 = 60. The Navy formula gives 495 / 1.0418 − 450 = 25.2%, which falls in the Obese category for men (25%+). Reducing your waist below about 101 cm would bring you under 25%.

Free Online Tool

Body Fat Calculator

Estimate body fat percentage using the U.S. Navy method

Reviewed by Prime Metric • Updated September 2026 WhatsApp

Your Measurements

Gender

Height (cm)

Neck (cm)

Waist (cm)

Results

16.9%

Fitness

Body Fat Percentage (BFP) estimated with the U.S. Navy method.

About this Tool

The Body Fat Calculator uses the U.S. Navy method to estimate body fat percentage based on circumference measurements. Unlike BMI, which only considers height and weight, this method accounts for body composition by measuring specific body parts. It's a practical way to assess fitness and health without expensive equipment.

Common Use Cases

Fitness Progress Tracking

Monitor body composition changes during weight loss or muscle building programs more accurately than scale weight alone.

Health Assessment

Evaluate health risks associated with body fat levels, as high body fat is linked to various health conditions.

Athletic Performance

Athletes can optimize performance by maintaining body fat within their sport's ideal range.

Goal Setting

Set realistic body composition goals and track progress toward them over time.

Pro Tips

!
Measure Consistently
Take measurements at the same time of day, ideally in the morning before eating, for consistent tracking.
!
Measure Accurately
Use a flexible measuring tape, keep it snug but not tight, and measure at the correct body locations (narrowest waist, fullest hip).
!
Track Trends
Single measurements can vary. Track weekly or monthly trends rather than day-to-day fluctuations.
!
Combine with Other Metrics
Use alongside photos, measurements, and how clothes fit for a complete picture of progress.

Examples

Man: 175 cm, neck 38 cm, waist 85 cm

A man with these measurements has about 16.9% body fat (Fitness category).

Waist minus neck: 85 − 38 = 47; log10(47) = 1.6721, log10(175) = 2.2430.
Density: 1.0324 − 0.19077 × 1.6721 + 0.15456 × 2.2430 = 1.0601.
Body fat: 495 / 1.0601 − 450 = 16.9% (Fitness for men is 14-18%).

Woman: 165 cm, neck 34 cm, waist 75 cm, hip 100 cm

A woman with these measurements has about 28.9% body fat (Average category).

Waist + hip − neck: 75 + 100 − 34 = 141; log10(141) = 2.1492, log10(165) = 2.2175.
Density: 1.29579 − 0.35004 × 2.1492 + 0.22100 × 2.2175 = 1.0335.
Body fat: 495 / 1.0335 − 450 = 28.9% (Average for women is 25-32%).

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