01 / FORMULA COMPARISON
Compare five skinfold formulas
The calculator applies five supported methods to your measurements: Jackson–Pollock 3-site, 4-site and 7-site; Durnin–Womersley 4-site; and Parrillo 9-site.
Each result shows the estimate, the measurements required and the formula used. If a method is incomplete, you’ll see what’s missing. This makes it easier to compare methods and understand why their estimates differ.
02 / HOW IT WORKS
How skinfold measurements estimate body fat
A skinfold caliper measures a fold of skin and underlying tissue at specified sites. Equations combine selected skinfolds with details such as age and sex to estimate body density. The calculator then converts that estimate into a body-fat percentage.
Each method uses its own sites and study population, so estimates can differ. A skinfold result is an estimate, not a direct measurement of total body fat or medical advice.
03 / DATA PRIVACY
Your measurements stay in your browser
Calculations run in your browser. If you allow local storage, your measurements, history and settings are saved in this browser on this device.
You don’t need an account or an upload to calculate. You choose whether to export your data or send selected measurements to FuelLens.
04 / TRENDS & HISTORY
Track measurement trends over time
Save measurements with their dates, then use Trends to compare body-fat estimates from each formula with weight, waist and hip measurements, BMI and other available metrics.
Choose a time range to view your charts and statistics. Measuring the same way each time makes results easier to compare.
05 / EXPORT & TRANSFER
Export and use your measurement data
Save a JSON backup to keep or restore your data. For analysis in a spreadsheet or AI tool, create a CSV with the fields you choose.
You can also select a date range and metrics to send to the FuelLens nutrition dashboard. Start the transfer in Settings.
FAQ
Frequently asked questions
Which skinfold body-fat formulas does the calculator use?
It evaluates five methods: Jackson–Pollock 3-site, 4-site and 7-site, Durnin–Womersley 4-site, and Parrillo 9-site. A result is calculated when its required measurements are available.
Why do the formulas give different body-fat estimates?
The methods use different skinfold sites, equations and study populations. Each result is an estimate, so comparing several methods can show how the chosen equation affects the value.
Are my skinfold measurements uploaded or stored online?
Calculations run in your browser. With local storage consent, measurements and history are saved in this browser on your device. You can choose to export or transfer selected data.
Can I export my measurements for backup or analysis?
Yes. Export a JSON backup to keep or restore your data, or create a CSV with selected fields for spreadsheet or AI-assisted analysis.
Can I send measurements to FuelLens?
Yes. In Settings, choose the time range and metrics you want to send, then start the transfer to the FuelLens nutrition dashboard.
Are skinfold body-fat results exact?
No. Skinfold equations estimate body-fat percentage from measurements and personal details. Results can vary by formula and measuring technique and are not medical advice.