Body Fat Percentage Calculator
Estimate body fat percentage from your gender selection, age, height, and weight. The calculator uses BMI and the Deurenberg formula; no body measurements are needed.
Deurenberg Body Fat Calculator
Percentage Body Fat Formula
Where:
- \(W\) — weight in kilograms (kg)
- \(H\) — height in meters (m)
- \(A\) — age in years
- \(G\) — 1 when Male is selected, or 0 when Female is selected
The Deurenberg formula estimates the percentage of body weight that is fat from BMI, age, and the selected gender category. Height entered in centimeters is converted to meters before BMI is calculated.
Percentage Body Fat – Calculation Example
Example: a 30-year-old selects Male and enters a height of 170 cm and a weight of 70 kg.
First, convert 170 cm to 1.70 m and calculate BMI:
\[\mathrm{BMI}=\frac{70}{1.70^2}\approx24.22\]
Using the unrounded BMI for the final calculation:
\[\mathrm{Body\ fat\ (\%)}=1.2\left(\frac{70}{1.70^2}\right)+0.23(30)-10.8(1)-5.4\approx19.77\%\]
Result: estimated body fat is 19.77%.
How to use the calculator
- Choose Male or Female in the Gender field. This choice sets the formula’s gender coefficient.
- Enter your Age in years.
- Enter your Height in centimeters. Use your measured height without shoes if possible.
- Enter your Weight in kilograms, then read the Body Fat result as a percentage.
The calculator uses the numbers you enter directly. Check the units before interpreting the result: entering a height in meters instead of centimeters, or a weight in pounds instead of kilograms, will give an incorrect estimate.
What estimated body fat percentage means
Body fat percentage describes the proportion of your total weight made up of fat. An estimate of 19.77%, for example, means that roughly 19.77% of body weight is estimated to be fat; it does not describe where that fat is located. The remaining weight includes muscle, bone, organs, water, and other tissues.
This calculator starts with body mass index (BMI), which relates weight to height. It then adjusts that value for age and the selected gender category. Two people with the same BMI can therefore receive different body fat estimates. Unlike BMI alone, the result is expressed as an estimated percentage of body weight, but it is still derived from height and weight rather than a direct measurement of fat.
Use the number as a rough indication of body composition, not a diagnosis or a precise target. A change in the result can reflect a change in weight even when you do not know whether fat, muscle, or water caused it. If you are tracking changes, compare results alongside consistent measurements and other information about your health.
Assumptions and practical limitations
The Deurenberg equation is a population-based estimate, not an individual body-fat test. It may be less representative for people whose muscle mass or body proportions differ substantially from those reflected by BMI—for example, highly muscular athletes. Age-related changes in body composition also vary between individuals. The formula cannot account for pregnancy, changes in hydration, or where fat is stored.
The formula uses only two gender coefficients: 1 for Male and 0 for Female. That is a limitation of the equation, not a complete description of anyone’s physiology or identity. The calculator is best treated as a general adult estimate; it should not be relied on for children or for medical decisions. It also requires a height greater than zero, even though the input field may allow zero.
For a useful comparison over time, weigh yourself under similar conditions and keep your height entry consistent. If your goal is to assess abdominal size relative to height, the waist-to-height ratio calculator answers a different question. If you have reliable skinfold measurements and want another way to estimate body fat, try the 3-point body fat calculator. Different methods use different inputs and may produce different results; avoid treating small differences between them as meaningful changes.
Frequently Asked Questions
What is a healthy body fat percentage?
There is no single healthy percentage for everyone. Reference ranges vary by age, sex, and the source used; a value considered typical for one group may not be appropriate for another. This calculator’s result is only an estimate, so avoid treating a small difference from a published range as a diagnosis. A healthcare professional can help interpret it in the context of your health.
How do I use pounds and inches with this calculator?
Convert pounds to kilograms by dividing by 2.20462, and convert inches to centimeters by multiplying by 2.54. For example, 150 lb is about 68.04 kg, and 66 in is 167.64 cm. Enter the converted values rather than the original numbers. Keep a few decimal places during conversion to avoid unnecessary rounding.
How can I calculate my estimated fat mass from the result?
Multiply your weight by the estimated body fat percentage divided by 100. For example, at 70 kg and an estimated 20% body fat, estimated fat mass is 14 kg. Subtract that from total weight to estimate fat-free mass: 56 kg in this example. Both figures inherit the uncertainty of the body fat estimate.
Will this calculator detect muscle gain or fat loss?
Not necessarily. If your weight stays the same while you gain muscle and lose fat, the estimate stays the same, provided your other inputs do not change. If muscle gain increases your weight, the estimate may even rise despite an improvement in body composition. For tracking progress, consider additional measurements rather than relying on this number alone.
Why did I get a negative body fat percentage or a result above 100%?
The equation does not restrict its output to physically possible percentages. Unusual or incorrect inputs can therefore produce a negative result or one above 100%. Check your age, height, weight, and units first; height must be greater than zero. Even with correct entries, an extreme result signals that this population-based estimate is not useful for your circumstances.
Is this estimate as accurate as a DXA scan?
No. A DXA scan measures body composition using imaging, while this calculator infers body fat from basic inputs. DXA can provide more detailed information, but its results also have measurement uncertainty and can vary with testing conditions. If body composition matters for a medical decision, discuss the appropriate assessment method with a qualified healthcare professional.