A free body fat calculator using the US Navy tape-measure method, with your fat and lean mass and the American Council on Exercise's ranges.
Estimate your body fat with a tape measure by the US Navy method, and see where it sits.
You
Entered once, used by every health calculator here, and saved only in this browser.
Your measurements
Measure with a soft tape, relaxed, without pulling it tight. Measure twice and use the average.
Your result
Fill in the fields above to see your result.
These calculators give general estimates for healthy adults, not medical advice. Talk to your doctor before you change how you eat or train, especially if you're pregnant, take medication or have a health condition.
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This free body fat calculator estimates your body fat with a tape measure, by the US Navy method.
Measure your waist and neck, and your hips for women, and it shows your percentage, your fat and lean mass, and where you sit on the American Council on Exercise's ranges.
I built it because body fat says far more than BMI, and the scans that measure it cost money. A tape measure and five minutes get you close.
Here's how the Navy method works, and how to measure well.
TL;DRKey takeaways
What is a body fat calculator?
A body fat calculator estimates what share of your weight is fat. This one uses the method Hodgdon and Beckett published for the US Navy in 1984.
For men, it uses your waist minus your neck against your height. For women, it uses waist plus hips minus neck, because women carry more fat at the hips.
How to use the body fat calculator
You need a soft tape measure and a minute.
Measure twice and use the average, without pulling the tape tight.
Body fat ranges
These are the American Council on Exercise's ranges.
- Women
- 10–13%
- Men
- 2–5%
- Women
- 14–20%
- Men
- 6–13%
- Women
- 21–24%
- Men
- 14–17%
- Women
- 25–31%
- Men
- 18–24%
- Women
- 32% and over
- Men
- 25% and over
Essential fat is what the body needs to work, so lower isn't always better.
A worked example
Here's the example the calculator loads when you press Try an example.
A man is 178 cm tall and weighs 78 kg, with an 85 cm waist and a 38 cm neck. The Navy method puts him at about 16.4% body fat, in the fitness range.
That's about 12.8 kg of fat and 65.2 kg of everything else. His BMI is 24.6, so here both numbers agree.
How to measure well
Small changes in the tape change the result, so do it the same way each time.
Same time, same place
Measure in the morning before you eat, standing relaxed. Breathe out normally before you read the waist.
Tape flat, not tight
Keep the tape level all the way round, touching the skin without pressing in.
Watch the trend
Measure every two to four weeks. A falling waist with a steady weight usually means fat down and muscle up.
Mistakes to avoid
These make a body fat estimate less useful.
- Sucking in your stomach for the waist
- Measuring at different spots each time
- Comparing a tape number with a scan number from another day
- Aiming for essential fat levels as a goal
Use your own trend more than any single result.
Muscle is the goal
Lowering body fat works best when you keep or build muscle at the same time.
Muscle is the organ of longevity.
The protein calculator and the one rep max calculator help with both sides of that.
Who is the body fat calculator for?
It's for anyone training or losing fat, and these tools go with it.
- BMI calculator – for the quick weight for height check
- Calorie calculator – for losing fat at a steady pace
- Protein calculator – for keeping your muscle as you lose
- One rep max calculator – for planning your strength training
- Biological age calculator – for how old your body really is
Measure today, then again in four weeks to see the trend.
More health calculators
Every health calculator reads the same "You", so you only enter yourself once.
| Calculator | What it answers |
|---|---|
| BMI calculator | Is my weight healthy for my height? |
| Ideal weight calculator | What's a good goal weight? |
| Macro calculator | How much protein, fat and carbs? |
| One rep max calculator | How strong am I? |
Pair your body fat with your macros to lose fat and keep muscle.
Plan your health with your AI
Take your numbers further in
Body Fat Calculator FAQs
Questions about the body fat calculator? Here's what to know.
A body fat calculator estimates what share of your weight is fat.
This free one uses the US Navy tape-measure method and the American Council on Exercise's ranges.
It uses your height, waist and neck, plus hips for women, in a formula Hodgdon and Beckett published in 1984.
It's usually within a few percentage points of a lab scan, and closer when you measure carefully.
Your trend over time is what matters most.
The American Council on Exercise puts fitness at 14% to 17% for men and 21% to 24% for women, and average at 18% to 24% and 25% to 31%.
At the navel, standing relaxed, after breathing out normally.
Women carry more fat at the hips, so the formula for women adds the hip measurement.
It tells you more, because it separates fat from muscle.
BMI is quicker, so many people use both.
Every two to four weeks, the same way each time.
No, it's a general estimate for healthy adults.
Talk to your doctor before you change how you eat or train, especially if you're pregnant, take medication or have a health condition.
Yes, it's free with no login, and your numbers stay in this browser.
I did.
I'm Navid Moazzez, and I made the body fat calculator as one of my free tools on navid.me.
More about me.
Navid Moazzez
AI business strategist & AI OS builder
Navid Moazzez helps creators and founders master AI and build their own AI Operating System (AI OS) to automate their business and life.
Navid.me is reader-supported. When you buy through links on this site, I may earn an affiliate commission. Learn more.
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