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Body fat calculator

Estimate your body fat percentage (U.S. Navy method).

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The Body fat calculator turns Sex, Height (cm), Neck (cm), Waist (cm), Hips (cm, women) into Body fat, instantly and for free. For instance, with Sex = Male, Height (cm) = 175, Neck (cm) = 38, Waist (cm) = 85 and Hips (cm, women) = 95 it returns Body fat = 16.94%.

How to use it

  1. Enter your values: Sex, Height (cm), Neck (cm), Waist (cm), Hips (cm, women).
  2. Read the result instantly: Body fat.

Frequently asked questions

What does the Body fat calculator actually compute?

It takes Sex, Height (cm), Neck (cm), Waist (cm) and Hips (cm, women) and derives Body fat from them. The calculation is live as you type, so the result updates on every change.

What information do I need to provide?

5 values: Sex, Height (cm), Neck (cm), Waist (cm) and Hips (cm, women). Nothing else is required — no account, no file upload.

Can you show a worked example?

With Sex = Male, Height (cm) = 175, Neck (cm) = 38, Waist (cm) = 85 and Hips (cm, women) = 95, the calculator returns Body fat = 16.94%. Those figures come from running this exact tool, so you can reproduce them by entering the same values.

What happens if I enter larger values?

It moves a lot. Using Sex = Female, Height (cm) = 193, Neck (cm) = 42, Waist (cm) = 94 and Hips (cm, women) = 105 instead, Body fat goes from 16.94% to 29.54% — which is why it is worth testing a few scenarios rather than trusting a single figure.

Which “Sex” option should I choose?

You can pick between « Male » and « Female ». Each one changes what the calculator works out, so switch and compare — the default is « Male ».

What does it give for smaller values?

Scaled down to Sex = Male, Height (cm) = 158, Neck (cm) = 34, Waist (cm) = 77 and Hips (cm, women) = 86, Body fat comes out at 16.71%. The relationship is worth checking at both ends before you rely on a single result.

When would I actually use this?

Getting a reference point before a check-up, setting a realistic target, and understanding why two people of the same weight can be in very different shape — and, the same act from the other side, putting a day's caffeine, salt, sugar or alcohol beside the ceiling a health body publishes for it.

What is the most common mistake?

Reading BMI as a measure of health. It cannot tell muscle from fat, which is why athletes routinely score as overweight and why it says little about an individual.

How accurate is it, and what are the limits?

Estimate only.

What is the difference between the Body fat calculator and the Lean body mass calculator?

This one returns Body fat; the Lean body mass calculator returns Lean body mass (kg) and Fat mass (kg). That is the whole difference — open the one whose figure you need.

Further reading

All guides →
ExplainerWhat Is a Good Body Fat Percentage?Body fat percentage is a better health signal than weight alone. Here are the healthy ranges by sex, how it's measured, and how to use it wisely.ExplainerWhat Is Lean Body Mass? LBM vs Fat MassLean body mass is everything in your body that isn't fat. Learn how the Boer formula estimates it and why it matters for health and training.ExplainerIs BMI Reliable? The Limitations of Body Mass IndexBMI is a quick screen, not a diagnosis. Learn what it misses — muscle, fat distribution, age — and what to check alongside it.ExplainerWhat Is a Healthy Waist-to-Height Ratio?Keeping your waist under half your height is a simple health marker. Learn what waist-to-height ratio means, how to measure, and why under 0.5 is the goal.ExplainerWhat Is Your Ideal Weight?There's no single ideal weight — it's a healthy range. Here's what the common formulas say, what they miss, and better ways to judge a healthy weight.ExplainerWhat Is Body Surface Area (BSA)?Body surface area estimates your body's external area in square metres. Here is how it is calculated and why clinicians use it to dose medicines.