Use this free body fat calculator to estimate your body fat percentage. Then compare the Navy method and the BMI method, in metric or imperial units.
Two methods in oneBody Fat Calculator
Because the scale cannot show fat, body fat percentage gives you a clearer picture. First, choose your units and sex. Then enter your age and measurements, and you get two estimates: one from the Navy method and one from the BMI method.
How to Use the Body Fat Calculator
- First, choose metric or imperial units, and select male or female.
- Next, enter your age, height, weight, waist and neck, plus your hip if you chose female.
- Then press Calculate Body Fat.
- Finally, read both estimates and your category.
What Is Body Fat Percentage?
Body fat percentage is the share of your total weight that is fat, because the rest is muscle, bone and water. Some fat is essential, because your body needs it for energy and vital functions. However, too much fat can raise the risk of obesity, heart disease and diabetes. Therefore, tracking it over time helps you follow your fitness progress.
The Two Methods Explained
First, this tool uses two well-known formulas. As a result, you can compare the figures and see how close they are.
First, it uses your height with waist, neck and, for women, hip. Therefore, it is one of the better estimates without special equipment. Read more on Wikipedia.
Instead, it uses your BMI, age and sex. It is simpler, but it cannot tell muscle from fat. Read about BMI from the CDC.
However, neither method matches a lab scan exactly. Still, both work well for tracking change over time.
BMI method formula
Body fat % = 1.20 × BMI + 0.23 × age − 10.8 × sex − 5.4 · sex = 1 for men, 0 for women
Healthy Ranges for Men and Women
First, these ranges show how body fat is usually grouped. As you can see, women naturally carry more essential fat than men.
| Category | Women | Men |
|---|---|---|
| Essential fat | 10-13% | 2-5% |
| Athletes | 14-20% | 6-13% |
| Fitness | 21-24% | 14-17% |
| Average | 25-31% | 18-24% |
| Obese | 32% and above | 25% and above |
Body Fat Calculator Examples
For example, here are three adults who used the calculator.
First, Daniel enters his age (30), height (178 cm), weight (78 kg), waist (84 cm) and neck (38 cm). Then the calculator shows his result. Finally, the Navy method gives 15.7%, while the BMI method gives 20.2%.
First, Maria enters her age (28), height (165 cm), weight (60 kg), waist (66 cm), neck (32 cm) and hip (94 cm). Then she reads her result. Finally, the Navy method gives 22.2%, while the BMI method gives 27.5%.
James chooses imperial units because he measures in inches. Then he enters his age (40), height (70 in), weight (190 lbs), waist (36 in) and neck (15.5 in). Finally, the Navy method gives 20.4%, while the BMI method gives 25.7%.
More Health Tools
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Trusted Guides to Read Next
If you want more detail, these trusted guides explain body fat in depth.
Body Fat Calculator FAQs
What is a healthy body fat percentage?
For men, 14-17% is generally fit, while 18-24% is average. Likewise, for women, 21-24% is fit, while 25-31% is average. However, essential fat, which is below these ranges, is the minimum needed for basic health.
How often should I measure myself?
Once every 2 to 4 weeks is usually enough. Because body fat does not change much from day to day, more frequent checks add little.
Is this body fat calculator accurate?
It gives a good estimate, but it is not a lab test. For example, a DEXA scan measures body fat more precisely. Therefore, use your result to track progress over time.
Is this suitable for children?
No, because both formulas are made for adults. Therefore, they are not accurate for children or teenagers who are still growing.
Which is better, the Navy method or the BMI method?
The Navy method is usually closer because it uses your waist and neck. By contrast, the BMI method cannot tell muscle from fat, so it can overestimate fat in muscular people.
Disclaimer: Because it only gives an estimate, this calculator is for general information and is not medical advice. However, for health decisions, please speak with a doctor or qualified professional.