Body Fat Calculator

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About the Body Fat Calculator

Body fat percentage tells you how much of your body weight is fat versus lean mass, and is generally a better indicator of fitness than weight alone.

Formula Used

Men: BF% = 495 / (1.0324 - 0.19077×log10(waist-neck) + 0.15456×log10(height)) - 450 Women: BF% = 495 / (1.29579 - 0.35004×log10(waist+hip-neck) + 0.22100×log10(height)) - 450 (all measurements in centimetres)

How It Works

This calculator uses the US Navy circumference method, which estimates body fat from your neck, waist, and (for women) hip measurements along with your height.

Step by Step

  1. Measure your neck, waist, and (for women) hip circumference in centimetres.
  2. Plug the values into the US Navy formula for your gender along with your height.
  3. The result is your estimated body fat percentage.

Worked Example

Example: A man, 180 cm tall, neck 38 cm, waist 85 cm:

BF% = 495 / (1.0324 - 0.19077×log10(85-38) + 0.15456×log10(180)) - 450 ≈ 15.6%

Reference Table

CategoryMenWomen
Essential Fat2-5%10-13%
Athletes6-13%14-20%
Fitness14-17%21-24%
Average18-24%25-31%
Obese25%+32%+

Frequently Asked Questions

How accurate is the Navy method?

It is a reasonably accurate estimate for most people, typically within a few percentage points of more precise methods like DEXA scans.

Where should I measure my waist?

Measure at the narrowest point of your torso, usually just above the belly button, without pulling the tape too tight.

What is a healthy body fat percentage?

For men, 10-20% is generally considered healthy, while for women it is typically 18-28%, though this varies with age and fitness goals.