Body fat estimate

Calculate body fat estimate with clear inputs and assumptions.

Your inputs stay in your browser. Displayed results are rounded to a maximum of 12 significant digits.

Method and assumptions

Method version 1.0.0 · Updated October 17, 2026

Calculate

Formula: Calculate body fat estimate with clear inputs and assumptions.

Calculate body fat estimate with clear inputs and assumptions.

bmi: BMI
age: Age
sex: Biological coefficient

Results are estimates where noted and depend on the entered assumptions.

Calculate with code

These short examples use the same inputs and core calculation as this tool. Adapt validation and formatting to your application.

JavaScript

const bmi = 24, age = 30, sexFactor = 1; // example coefficient
console.log(1.2*bmi + 0.23*age - 10.8*sexFactor - 5.4); // population estimate only

TypeScript

const bmi=24, age=30, sexFactor=1;
const estimate: number = 1.2*bmi + .23*age - 10.8*sexFactor - 5.4;
console.log(estimate); // formula estimate, not a measurement

Python

bmi, age, sex_factor = 24, 30, 1
print(1.2*bmi + .23*age - 10.8*sex_factor - 5.4)  # estimate only

Java

System.out.println(1.2*24 + .23*30 - 10.8*1 - 5.4); // estimate only

Console.WriteLine(1.2*24 + .23*30 - 10.8*1 - 5.4); // estimate only