How to use the Body Fat Percentage Calculator
- Enter your values. Fill in Sex, Height, Neck, Waist, Hip and Weight. Example values are pre-filled so you can see how it works.
- Get instant results. Results update automatically as you type — no need to press anything (or click Calculate).
- Review the breakdown. Check the detailed results, charts and tables below the main answer.
- Save or share. Copy the result, print it, or use “Share link” to send the exact calculation to someone.
About this tool
BMI, calorie, macro, body fat, heart rate, pregnancy and fitness calculators.
Read the complete Body Fat Percentage Calculator guide
Frequently asked questions
Is the Body Fat Percentage Calculator free to use?
Yes. The Body Fat Percentage Calculator on Gemma-4 is 100% free with no sign-up, no limits and no watermark. An optional free account lets you save favourites.
Is my data private?
Yes. Your inputs are processed instantly and are not stored on our servers.
Does it work on mobile phones?
Absolutely. The Body Fat Percentage Calculator is fully responsive and works on Android, iPhone, tablets and desktop browsers such as Chrome, Edge, Safari and Firefox.
What formula does the Body Fat Percentage Calculator use?
It uses: US Navy: 495 / (1.0324 − 0.19077·log(waist − neck) + 0.15456·log(height)) − 450. All calculations run with full precision and are rounded only for display.
How accurate is the Body Fat Percentage Calculator?
The calculator uses standard, well-established formulas and exact arithmetic. Results are as accurate as the values you enter; for financial, medical or legal decisions, confirm with a qualified professional.
Who is the Body Fat Percentage Calculator useful for?
It is popular with people starting a fitness journey, athletes and gym-goers, parents tracking a child’s growth — anyone who needs quick, reliable help with health and fitness goals.