What is a more accurate alternative to this calculator?

DEXA scans, hydrostatic weighing, and bioelectrical impedance devices are all more precise.

Body Fat Calculator - Health Management

Q: Is the U.S. Navy method accurate?

It's a reasonably reliable estimate using tape measurements, though less precise than lab methods like DEXA scans.

Q: Why do women need a hip measurement but men don't?

The formula was developed separately per gender based on typical fat distribution patterns.

Q: What is a healthy body fat percentage?

For men, 14 to 24% is generally fit-to-average. For women, 21 to 31%.

Q: Is body fat percentage more important than BMI?

They measure different things. Using both gives a more complete picture than either alone.

Q: Can I have a healthy BMI but high body fat?

Yes, sometimes called skinny fat, where BMI is normal but body fat percentage is higher than ideal.

Q: How often should I recheck my body fat percentage?

Every 3 to 4 weeks is reasonable to track meaningful trends.

Q: Does age affect healthy body fat ranges?

Body fat tends to increase somewhat with age due to gradual muscle loss.

📏 Calculate Your Body Fat %

Gender

Height (cm)

Neck Circumference (cm)

Waist Circumference (cm)

Weight (kg)

What Is Body Fat Percentage?

Body fat percentage is the proportion of your total body weight that is made up of fat, versus lean mass (muscle, bone, organs and water). For example, a 70 kg person with 14 kg of fat has a body fat percentage of 20%. Unlike weight alone, it gives a much clearer picture of body composition and fitness.

How This Calculator Works

This calculator uses the U.S. Navy Method, which estimates body fat from simple tape-measure measurements rather than expensive equipment. You'll need your height, neck, waist, and — for women — hip circumference, alongside your weight to calculate fat and lean mass.

Formula Used (U.S. Navy Method)

Gender	Formula
Men	86.010 × log₁₀(waist − neck) − 70.041 × log₁₀(height) + 36.76
Women	163.205 × log₁₀(waist + hip − neck) − 97.684 × log₁₀(height) − 78.387

Important: these constants are calibrated for measurements in inches. If you measure in centimetres, convert to inches first (or simply use the calculator above, which converts automatically regardless of which unit you enter).

Body Fat Percentage Categories

Category	Men	Women
Essential Fat	2–5%	10–13%
Athletes	6–13%	14–20%
Fitness	14–17%	21–24%
Average	18–24%	25–31%
Obese	25%+	32%+

Example Calculation

For a male, 175 cm tall (68.9 in), neck 38 cm (15.0 in), waist 85 cm (33.5 in), weighing 80 kg:

Body Fat % = 86.010 × log₁₀(33.5−15.0) − 70.041 × log₁₀(68.9) + 36.76 ≈ 17.0% (right at the Fitness/Average boundary — see the category table below)
Fat Mass = 80 × 17.0% ≈ 13.6 kg
Lean Mass = 80 − 13.6 ≈ 66.4 kg

Why Body Fat Is More Useful Than Weight

Two people can weigh exactly the same but have very different body compositions — one might carry more muscle and less fat than the other. The person with lower body fat is generally fitter and at lower metabolic risk, even at an identical weight and height. This is why body fat percentage often tells a more useful story than the number on the scale alone.

💡 Good to Know Body fat naturally includes some "essential fat" needed for hormone production and organ protection — the goal isn't zero body fat, but a healthy range for your gender and activity level.

Body Fat vs BMI

BMI	Body Fat %
Tells you if your weight is in a typical range for your height	Tells you how much of that weight is actually fat
Can misclassify muscular individuals as overweight	Distinguishes muscle from fat directly

For the most complete picture, check your BMI alongside your body fat percentage.

Tips to Reduce Body Fat

Maintain a moderate, sustainable calorie deficit
Increase protein intake to help preserve lean muscle
Combine strength training with regular cardio
Stay consistent with workouts over weeks, not just days
Prioritise 7–8 hours of quality sleep nightly

Limitations to Keep in Mind

This is an estimate — not a lab-precise measurement
Measurement technique (tape tension, position) can affect accuracy
More precise methods include DEXA scans, hydrostatic weighing, or bioelectrical impedance analysis
Best used to track trends over time rather than as a single exact figure

⚠️ Not medical advice This calculator provides an estimate for educational purposes only. Always consult a qualified healthcare professional for personalised guidance.

Frequently Asked Questions

Is the U.S. Navy method accurate?+

It's a reasonably reliable estimate for most body types using only tape measurements, though it's less precise than lab methods like DEXA scans.

Where exactly should I measure my neck and waist?+

Measure your neck just below the larynx, and your waist at the narrowest point (or at the navel if there's no clear narrowing). Keep the tape snug but not compressing the skin.

Why do women need a hip measurement but men don't?+

The formula was developed separately for each gender based on typical fat distribution patterns — women's formula includes hip measurement to improve accuracy for typical female fat distribution.

What is a healthy body fat percentage?+

For men, 14–24% is generally considered fit-to-average; for women, 21–31% — see the full category table above for more detail.

Is body fat percentage more important than BMI?+

They measure different things — body fat tells you body composition, while BMI is a quick screening tool. Using both gives a more complete picture than either alone.

Can I have a healthy BMI but high body fat?+

Yes — this is sometimes called "skinny fat," where someone has a normal BMI but a higher-than-ideal body fat percentage due to low muscle mass.

How often should I recheck my body fat percentage?+

Every 3–4 weeks is a reasonable interval to track meaningful trends without over-focusing on short-term fluctuations.

What's a more accurate alternative to this calculator?+

DEXA scans, hydrostatic (underwater) weighing, and bioelectrical impedance devices are all more precise, though less accessible than a simple tape measurement.

Does age affect healthy body fat ranges?+

Body fat naturally tends to increase somewhat with age even at a stable weight, due to gradual muscle loss — so ranges are typically viewed a bit more flexibly for older adults.

Can this calculator be used for athletes?+

It can, though very muscular or lean athletes may find the estimate slightly less precise than for average body types — a DEXA scan is more reliable in these cases.