Deurenberg Body Fat Calculator

About this calculator

The Deurenberg formula estimates body fat percentage using just Body Mass Index, age, and sex — no calipers, scans, or specialized equipment required — making it a practical alternative to more invasive body composition measurement methods. The formula, published by Deurenberg and colleagues in 1991, is: Body Fat % = (1.20 × BMI) + (0.23 × Age) − (10.8 × sex) − 5.4, where sex is entered as 1 for male and 0 for female.

Because the formula relies on BMI, it inherits BMI’s known limitation of not distinguishing muscle mass from fat mass, so it can overestimate body fat in very muscular individuals and underestimate it in those with low muscle mass, and its accuracy was derived from and validated primarily on adult populations. It remains useful as a quick population-level or general estimate, but is not considered as precise as DEXA scans, hydrostatic weighing, or bioelectrical impedance analysis for individual clinical decisions.