Interpretation
Your estimate will appear here.
This is a screening estimate. It is not a medical diagnosis or a substitute for professional advice.
Enter Your Measurements
Use a flexible tape. Keep it level and avoid pulling it tight.
Example Data
These example values show the format expected by the calculator. Results are approximate and can vary with tape placement.
| Profile | Height | Neck | Waist | Hip | Weight | Estimated body fat |
|---|---|---|---|---|---|---|
| Male example | 178 cm | 38 cm | 86 cm | Not used | 77 kg | About 17.3% |
| Female example | 165 cm | 32 cm | 74 cm | 101 cm | 64 kg | About 30.2% |
Formula Used
The calculator applies the U.S. Navy body-circumference equations. Measurements are converted to inches before calculation when metric units are selected.
Male equation
− 70.041 × log10(height) + 36.76
Female equation
− 97.684 × log10(height) − 78.387
The estimate also calculates fat mass as body weight multiplied by body-fat percentage. Lean mass equals body weight minus estimated fat mass.
How to Use This Calculator
- Select the equation that matches the requested measurement profile.
- Choose metric or imperial units before entering any value.
- Measure height, neck, and waist with a flexible tape.
- Enter hip circumference when using the female equation.
- Add body weight to receive fat mass, lean mass, and BMI.
- Press Calculate body fat. Review the result above the form.
- Download CSV or PDF after checking the measurement details.
Understand Body-Fat Estimates
Understanding Circumference Estimates
Body circumference methods estimate body fat from measurements. The calculator uses a tape measure, your height, and standard sex-specific equations. Men use neck, waist, and height. Women use neck, waist, hip, and height. Optional body weight adds estimated fat mass, lean mass, and body mass index. They do not replace clinical testing or medical advice.
Tape placement matters more than expensive equipment. Measure the neck below the larynx. Keep the tape level. Measure the waist at your site after a relaxed exhale. Measure the hip at its widest point. Stand naturally. Do not pull the tape tight. Take two or three readings. Use their average when readings differ.
Use Consistent Measurement Conditions
Measure at the same time whenever possible. Avoid measuring after a large meal, hard workout, or long flight. Hydration, posture, and tape tension can change numbers. Record the unit system and waist location. Look for trends across several weeks.
This calculator converts metric inputs internally before applying the equation. It then returns the selected display unit. The estimate is most useful when the same method is repeated. Switching waist locations can create a false change. Keep a simple log with date, body weight, and notes. Progress photos and training performance can add helpful context.
Read Results With Care
The body-fat percentage is an estimate. It can differ from DEXA, skinfolds, or laboratory methods. The chart places your result beside broad adult reference bands. Those bands are screening guides. Pregnancy, illness, large muscle mass, and body-shape differences can limit accuracy.
Use the fat-mass estimate to understand how many kilograms or pounds are likely fat. Lean mass is everything else. Compare changes using similar conditions. Slow, steady movements are more meaningful than one isolated result. Speak with a qualified clinician before making aggressive nutrition or exercise changes.
Build a Practical Tracking Routine
Choose one day each week or month. Use the same tape and measurement points. Enter results, then download a CSV record when needed. The PDF option creates a shareable summary. The Plotly gauge offers a quick visual check.
Set goals around habits and body composition. Include sleep, protein intake, strength training, walking, and recovery. A useful target can be maintaining lean mass while reducing fat slowly. Review the trend every four to eight weeks. Adjust only when several measurements point in the same direction. Consistent actions matter more than perfect estimates.
Frequently Asked Questions
1. Is this calculator accurate?
It provides a body-fat estimate based on circumference equations. Accuracy depends on correct tape placement and repeatable technique. Individual body shape can affect results. Use it mainly to compare your own measurements over time.
2. Why does the female equation need hip circumference?
The female circumference equation includes hip size because body-fat distribution often differs by sex. Hip measurement is combined with waist, neck, and height to create the estimate.
3. Should I use centimeters or inches?
Either unit system works. Select one system and use it for every circumference value. The calculator converts metric measurements internally before applying the equation.
4. Where should I measure my waist?
Use one clearly defined location, such as navel level or natural waist. Follow the same location during later checks. Consistency is more useful than switching among sites.
5. Why is body weight optional?
Weight is not required for the circumference formula. It is optional because it allows the calculator to estimate fat mass, lean mass, and BMI.
6. How often should I measure?
Weekly or monthly checks are often enough. Daily changes can reflect water, meals, and normal variation. Measure under similar conditions for the clearest trend.
7. Can I use this during pregnancy?
This calculator is not designed to assess pregnancy-related body changes. Discuss body composition, nutrition, and weight changes with a qualified prenatal healthcare professional.
8. Why does my result differ from a smart scale?
Smart scales use bioelectrical impedance. This tool uses tape measurements and an equation. Hydration, device settings, and body proportions can produce different estimates.
9. Can athletes use the calculator?
Athletes can use it for consistent tracking. However, unusually high muscle mass or body proportions may reduce agreement with other methods. Consider professional assessment for performance decisions.
10. What does lean mass mean here?
Lean mass is body weight minus estimated fat mass. It includes muscle, bone, organs, water, and other non-fat tissues. It is still an estimate.
11. Can I save the calculation?
Yes. After calculating, download a CSV file for spreadsheets or a PDF summary for printing and sharing. Keep the same measurement method in each record.