female, 165 cm height
- Fat mass
- 20.22 kg
- Lean mass
- 47.78 kg
- Method
- Navy-style tape
Body Fat Calculator
Use this free body fat calculator to estimate body fat percentage, fat mass, and lean mass from height, weight, neck, waist, and hip measurements.
Estimate, not diagnosis Formula notes Example inputs Tab-only history
Formula steps
- Convert tape measurements to inches for the Navy-style circumference equation.
- Use waist plus hip minus neck with height in the female equation.
- Treat the result as an estimate for consistent trend tracking, not diagnosis.
How to use the Body Fat Calculator
- Enter the requested measurements, dates, lab values, or workout details.
- Check that the units and formula assumptions match what the tool is asking for.
- Press the calculate button to see the answer, supporting metrics, and formula steps.
- Read the estimate with the health disclaimer in mind, then copy the result if you need it for notes.
What people use it for
Estimate body fat percentage without a scale that measures body composition.
Track tape-measure changes over time.
Compare estimated fat mass and lean mass.
Use alongside BMI for a broader screening picture.
Quick examples
Female tape example
165 cm, 68 kg, neck 34, waist 78, hips 98About 29.74% body fat
Male tape example
180 cm, 84 kg, neck 40, waist 88About 16.94% body fat
Trend check
170 cm, 72 kg, neck 35, waist 82, hips 101About 31.41% body fat
Need the guide or a nearby tool?
Need a slower walkthrough, a related calculator, or the full library? These links keep you close to the task you started.
- How to use the Body Fat Calculator See slower examples, input meanings, formula notes, result limits, and mistakes to avoid.
- Health & Fitness Browse related calculators and utilities in the same category.
- Calculator and utility guides Find more guides that use real tool inputs and example numbers.
- All free tools Search every live tool, converter, calculator, AI helper, and browser utility.
Frequently asked questions
Plain-language answers about when to use the estimate, what the formula means, what it cannot decide for you, and how privacy works.
When should I use the Body Fat Calculator?
Use it for simple educational checks, trend tracking, or planning tasks like these: Estimate body fat percentage without a scale that measures body composition. Track tape-measure changes over time. It can help you understand a number, but it cannot explain your whole health situation.
What do the main Body Fat Calculator inputs mean?
Enter formula sex, height, optional weight, neck, waist, and hip when the female equation is selected. The male equation uses waist minus neck with height. The female equation uses waist plus hip minus neck with height. Keep the tape level, snug, and consistent from one check to the next.
What is the Body Fat Calculator doing with my inputs?
In plain language: The calculator uses the common Navy-style circumference method: male estimate = 86.01 x log10(waist - neck) - 70.041 x log10(height) + 36.76; female estimate = 163.205 x log10(waist + hip - neck) - 97.684 x log10(height) - 78.387, with measurements converted to inches. Read the result together with the notes on the page, because health and fitness numbers often need personal context.
How should I read the Body Fat Calculator result?
Read the percentage as a Navy-style tape-method estimate, then use fat mass and lean mass as context if you entered weight. Small changes can come from tape placement, posture, breathing, or tension, so this is better for consistent trend checks than one-time diagnosis.
What formula does this body fat calculator use?
It uses the common Navy-style circumference equations. Male estimates use waist minus neck with height. Female estimates use waist plus hip minus neck with height. The calculator converts centimeters to inches internally because the published equation constants are inch-based.
Where should I measure neck, waist, and hips?
Use the same tape sites every time. For the neck, measure below the larynx without including shoulder muscles. For the waist, keep the tape level and measure after a normal relaxed exhale. For hips, measure around the widest part. A different site can change the answer quickly.
Why is weight optional?
Weight is not part of the percentage equation, but it lets the calculator estimate fat mass and lean mass. For example, 29.74% at 68 kg is about 20.22 kg estimated fat mass and 47.78 kg estimated lean mass.
Can I use this as medical advice?
No. This page provides an educational estimate only. Talk with a qualified health professional before making medical, pregnancy, nutrition, medication, or safety decisions. Use the calculator as a learning tool, then ask a qualified professional about decisions that affect care, pregnancy, medication, nutrition, or safety.
What should I double-check before trusting the result?
Check the units, date, and personal details before reading the answer. For example, pounds and kilograms, inches and centimeters, or a wrong activity level can change the result quickly. If the number feels surprising, rerun it slowly and compare it with the examples.
Does the site save my health inputs?
No. The calculator runs in your browser tab. Recent answers stay only on the page while you use it, and they are not sent to a server.