How to Calculate Your Body Fat Percentage (5 Methods Compared)

Why Body Fat Percentage Matters More Than Weight

Your scale weight tells you almost nothing about your health. Two people at 180 lbs can look completely different — one might be a lean athlete, the other sedentary with excess fat.

Body fat percentage tells you how much of your weight is fat versus lean mass (muscle, bone, water, organs). It's a far better indicator of health risk than weight or even BMI alone.

Healthy Body Fat Ranges

Women naturally carry more body fat due to hormonal differences and reproductive needs. This is normal and healthy.

Calculate Yours Now

Use our body fat calculator — it uses the U.S. Navy Method, one of the most accessible and reasonably accurate approaches:

5 Ways to Measure Body Fat

1. U.S. Navy Method (Free, At Home)

How it works: Uses neck, waist, and hip circumference measurements with a formula developed by the U.S. Navy.

Accuracy: ±3-4% compared to DEXA Cost: Free (just need a tape measure) Best for: Quick baseline estimate at home

This is what our calculator above uses. Measure first thing in the morning for consistency.

2. Skinfold Calipers

How it works: Pinch skin at 3-7 body sites, measure the fold thickness with calipers, plug into a formula.

Accuracy: ±3-4% (highly dependent on the person measuring) Cost: $5-15 for calipers Best for: Tracking changes over time (same person should always measure)

Common sites: triceps, chest, subscapular (below shoulder blade), midaxillary, suprailiac (above hip), abdominal, thigh.

3. Bioelectrical Impedance (BIA)

How it works: Sends a tiny electrical current through your body. Fat resists electricity more than muscle (which contains water), so resistance = fat estimate.

Accuracy: ±4-5% (heavily affected by hydration) Cost: $20-100 (smart scales) or free at many gyms Best for: Convenient daily tracking, but treat individual readings with skepticism

Tips for accuracy: Measure at the same time daily, well-hydrated but not right after drinking water, not after exercise.

4. DEXA Scan

How it works: Dual-energy X-ray absorptiometry — a low-dose X-ray that differentiates bone, fat, and lean tissue.

Accuracy: ±1-2% (gold standard for most purposes) Cost: $50-150 per scan Best for: Accurate baseline measurement, also shows fat distribution and bone density

This is considered the most practical clinical standard. It shows exactly where your fat is stored, which matters for health risk assessment.

5. Hydrostatic Weighing

How it works: You're weighed underwater. Since fat is less dense than lean tissue, your underwater weight reveals your body composition.

Accuracy: ±1-2% Cost: $30-75 per test Best for: Very accurate, but uncomfortable (you have to exhale completely while submerged)

Which Method Should You Use?

For most people, the Navy Method or a BIA scale is sufficient. If you want a truly accurate number, get a DEXA scan once, then track relative changes with a cheaper method.

Common Mistakes

1. Comparing methods — A BIA scale reading and a DEXA scan will give different numbers. Pick one method and stick with it.

2. Obsessing over the number — Body fat percentage fluctuates daily. Focus on the trend over weeks, not individual readings.

3. Ignoring where fat is stored — Visceral fat (around organs) is far more dangerous than subcutaneous fat (under skin). Waist circumference is a good proxy.

4. Measuring at different times — Hydration, food, and exercise all affect readings. Always measure under the same conditions.

Key Takeaways

• Body fat percentage is more meaningful than scale weight for health assessment
• The U.S. Navy Method is free, easy, and accurate within ±3-4%
• DEXA scans are the practical gold standard (±1-2%)
• Pick one method and track trends, don't compare across methods
• Healthy ranges differ significantly between men and women
• Where fat is stored matters as much as how much you have