How to Measure Body Fat Percentage at Home (Navy Method)

Why Measuring Body Fat Percentage at Home Is Worth It

Learning how to measure body fat percentage gives you something BMI cannot: it separates fat mass from muscle mass. Two people can share an identical BMI of 27 — one might be a lean athlete with 14% body fat, the other might carry 30%. Only a body fat measurement reveals the difference.

The US Navy circumference method is the most practical at-home option. It requires nothing but a soft measuring tape and takes about three minutes. Studies place its accuracy within 3–4 percentage points of DEXA scans for most adults — good enough for tracking progress over time.

Measure your body fat percentage now with the free Body Fat Calculator

Step 1: Get a Soft Measuring Tape

Use a fabric or flexible plastic measuring tape — the kind used in tailoring. A rigid metal tape cannot follow body contours accurately and will produce inflated readings.

The tape should be snug against the skin but not compressing it. You should be able to slide two fingers under the tape at most.

Step 2: Take the Required Measurements

The Navy formula needs different measurements depending on sex.

For men — three measurements:

1. Height — stand barefoot against a wall, heels together
2. Neck — measure just below the Adam's apple, tape perpendicular to the spine
3. Waist — measure at the level of the navel (belly button), not the narrowest point

For women — four measurements:

1. Height — same as above
2. Neck — same as above
3. Waist — at the narrowest point (typically between the navel and ribcage)
4. Hips — at the widest point, usually across the hip bones and buttocks

Step 3: Record in Consistent Units

Use either all centimetres or all inches — do not mix. The formulas below use centimetres, which is generally easier to work with.

Measurement tips for accuracy:

• Take measurements in the morning on an empty stomach
• Measure three times and use the average of all three readings
• Stand straight with feet together, breathing normally — do not hold your breath or suck in
• For the waist: measure at belly button level (men) or narrowest point (women), not wherever feels smallest

Step 4: Enter Into the US Navy Formula

Men's formula:

BF% = 86.010 × log₁₀(waist − neck) − 70.041 × log₁₀(height) + 36.76

Women's formula:

BF% = 163.205 × log₁₀(waist + hips − neck) − 97.684 × log₁₀(height) − 78.387

Worked example — male, height 180 cm, waist 90 cm, neck 40 cm:

log₁₀(90 − 40) = log₁₀(50) = 1.699 log₁₀(180) = 2.255

BF% = 86.010 × 1.699 − 70.041 × 2.255 + 36.76 BF% = 146.13 − 157.94 + 36.76 BF% = 24.9%

According to the ACE table below, this places a man in the "Acceptable" category.

The free Body Fat Calculator runs these logarithms for you — all you need are your tape measurements.

Step 5: Compare to ACE Categories and Set a Goal

The American Council on Exercise (ACE) publishes widely used reference ranges. These are descriptive benchmarks, not clinical thresholds — your personal health targets should factor in age and overall fitness.

Our example result of 24.9% (male) sits at the top of "Acceptable" — one percentage point from "Obese." A realistic near-term goal for this individual would be reducing to 20–22%, achievable with a modest calorie deficit paired with resistance training.

Pair this measurement with your BMI result and a daily calorie target to build a complete picture of where you are and where you want to go.

Conclusion

Key takeaways:

• The Navy tape method is the most accurate body fat measurement approach available at home
• Men need height, neck, and waist; women additionally need hips
• Measure three times and average; always take readings on an empty stomach in the morning
• The ACE "Fitness" range is 14–17% for men and 21–24% for women
• A single BMI number misses the lean-mass vs fat-mass distinction that body fat percentage reveals
• Use the free Body Fat Calculator to get your percentage without manual logarithm calculations