Estimate body fat percentage from BMI with an age and gender adjustment. Enter BMI, age, and gender for a quick estimate. Health data never leaves your device — every calculation runs locally in your browser.
Content reviewed October 2026 · About Toolzum
Calculate body fat percentage using the US Navy circumference method. Enter waist, neck, height, and hip measurements. Health data never leaves your device — every calculation runs locally in your browser.
Estimate your blood alcohol concentration (BAC) based on drinks consumed, weight, gender, and time elapsed. For educational purposes only. Health data never leaves your device — every calculation runs locally in your browser.
Computes Body Mass Index from metric or imperial height and weight inputs, categorizing the result into underweight, normal, overweight, and obese, with a healthy weight range for your height. Health data never leaves your device — every calculation runs locally in your browser.
Computes exact age in years, months, and days from a given birth date relative to any target date. Numbers never leave your device — every calculation runs locally in your browser.
Calculate customer churn rate by dividing customers lost by total customers. Monitor retention health for your subscription business. Numbers never leave your device — every calculation runs locally in your browser.
The formula uses BMI, age, and gender to estimate body fat percentage: BF% = (1.20 × BMI) + (0.23 × Age) - (10.8 × Gender) - 5.4, where Gender = 1 for male, 0 for female.
Typically within a few points of DEXA for average builds — an estimate for general fitness tracking, not a clinical measure. Less accurate for athletes with high muscle mass, elderly, or very lean individuals. Defaults (BMI 24, age 30, male) estimate 19.5%.
Essential fat, athletes, fitness, acceptable, and obese ranges for both men and women. These follow WHO and ACSM guidelines.
Your BMI, age, and gender — enter a BMI you already know or compute one first with the BMI calculator.
No. All calculations run locally in your browser. No health data is transmitted.
Body Fat Percentage Calculator
Calculate body fat percentage using the US Navy circumference method. Enter waist, neck, height, and hip measurements. Health data never leaves your device — every calculation runs locally in your browser.
BMI Calculator
Computes Body Mass Index from metric or imperial height and weight inputs, categorizing the result into underweight, normal, overweight, and obese, with a healthy weight range for your height. Health data never leaves your device — every calculation runs locally in your browser.