How to Measure Body Fat at Home With a Tape Measure

You can estimate body fat at home with a flexible tape measure and the US Navy method. Measure your height, neck and waist (and hips if you're a woman), and a formula turns them into a body fat percentage. It's usually within 3–4 points of a lab scan. The Body Fat Calculator does the maths and also shows your fat mass and lean mass.

How do I measure for the US Navy method?

Use a soft, non-stretch tape. Measure on bare skin, standing relaxed, after breathing out normally. Don't pull the tape tight enough to press into the skin.

1. Height: without shoes, standing straight against a wall.
2. Neck: just below the Adam's apple, with the tape sloping slightly down at the front.
3. Waist:
   • Men: around the belly at the navel.
   • Women: at the narrowest point of the waist.
4. Hips (women only): around the widest part of the buttocks.

Take each measurement twice and use the average. Measure in the morning before eating, at the same spots every time.

How does the calculation work?

The US Navy formulas (centimetre version) are:

• Men: 495 ÷ (1.0324 − 0.19077 × log₁₀(waist − neck) + 0.15456 × log₁₀(height)) − 450
• Women: 495 ÷ (1.29579 − 0.35004 × log₁₀(waist + hip − neck) + 0.221 × log₁₀(height)) − 450

Example: a man who is 180 cm tall with a 38 cm neck and an 85 cm waist.

• Waist − neck = 47 cm
• The formula gives about 16% body fat, in the "fitness" range.
• At 80 kg, that's roughly 13 kg of fat mass and 67 kg of lean mass.

The Body Fat Calculator works in cm or inches and shows where your result falls on a coloured scale.

What body fat percentage is healthy?

The calculator uses these American Council on Exercise ranges:

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% or more	32% or more

Women naturally carry more essential fat, so their ranges are higher. Very low body fat isn't healthier: it can affect hormones, energy and, in women, periods.

Body fat vs BMI: which is better?

BMI only uses height and weight, so it can't tell muscle from fat. Two people with the same BMI can have very different body fat. Body fat percentage gives a better picture of body composition, while waist size tells you about the riskier fat around the organs. Using all three together is the most useful. See what a healthy BMI is and what your waist-to-hip ratio means.

Why does my result look wrong?

• The tape was too tight or loose. A 2 cm error in the waist changes the result by a couple of points.
• Wrong waist spot. Men measure at the navel; women at the narrowest point.
• Bloating or a large meal. Measure in the morning for consistency.
• Very muscular necks (for example in wrestlers) can make the estimate too low.

If the calculator says the measurements give an impossible result, check you entered the neck smaller than the waist and the right units.

Other ways to measure body fat

• DEXA scan: very accurate, but expensive and needs a clinic.
• Smart scales (bioimpedance): convenient but strongly affected by hydration.
• Skinfold callipers: accurate in trained hands, harder to do on yourself.

For home use, the tape method is cheap, repeatable and good enough to see whether your training and diet are working.

Track your progress

Measure every two to four weeks and watch the trend rather than single readings. If you're losing fat while keeping strength, your macros and training are on track. Start with the free Body Fat Calculator, and pair it with the Macro Meal Planner to plan your eating. Your measurements stay in your browser and are never uploaded.