Body Fat Calculator
This body fat calculator estimates your body fat percentage using just a tape measure, in seconds. Enter your sex, height and three measurements. It returns your percentage, the range you fall into, and how much of your weight is fat versus lean mass.
Estimate based on the US Navy method (circumferences). The margin is around 3 to 4 points versus tests like bioimpedance and DEXA.
Quick summary
- The formula uses the US Navy method: neck, waist and height, plus hip for women.
- Measure with a tape, snug but not tight, in the morning and relaxed.
- A healthy range sits around 10 to 20% for men and 18 to 28% for women.
- The number drops with a real calorie deficit, not with the scale.
How to measure before you calculate
Your result is only as good as your measurements. Use a flexible tape, rest it against the skin without squeezing, and stand relaxed.
- Neck: just below the Adam's apple, with the tape angled slightly down in front.
- Waist: for men, at the navel. For women, at the narrowest point of the torso.
- Hip (women only): at the widest part of the glutes.
Measure twice and use the average. First thing in the morning, the number is steadier.
What is body fat percentage
Body fat percentage is the share of your weight that comes from fat, not muscle, bone and water. Two bodies at the same weight can have very different percentages.
That is why the scale misleads. You can lose fat, gain muscle and see the weight stand still. The percentage shows what actually changed.
Body fat ranges by sex
The ranges differ between men and women because women carry more essential fat. The table below follows the reference from the American Council on Exercise.
| Range | Women | Men |
|---|---|---|
| Essential fat | 10 to 13% | 2 to 5% |
| Athletes | 14 to 20% | 6 to 13% |
| Fitness | 21 to 24% | 14 to 17% |
| Acceptable | 25 to 31% | 18 to 24% |
| Above range | 32% or more | 25% or more |
For most people, a healthy target sits in the fitness or acceptable range. Very low percentages are neither sustainable nor advised without professional guidance.
Body fat or BMI: which to trust
BMI uses only weight and height. It is fast, but it does not separate fat from muscle, so it labels muscular people as overweight and hides the fat of those with little muscle.
Body fat percentage fixes that. Use both together: BMI for a quick read and body fat for your real composition.
How to lower your body fat
Cutting body fat is simple to describe and hard to keep up. Three points carry almost all of the result:
- A moderate calorie deficit: eat a little less than you burn, without crash cuts that trigger the yo-yo effect.
- Enough protein: it protects muscle while fat drops, so the percentage improves faster.
- Strength training: it keeps or builds lean mass, which shifts your composition even at a stable weight.
What stalls most people is not knowing whether they are actually in a deficit.
Watch your body fat actually go down
Body fat only drops when the deficit is real. ContaCal counts your plate's calories from a photo and shows whether you are truly in a deficit, with no spreadsheet and no guessing.
Try it Free →Frequently asked questions
How do I calculate body fat without a device?
You can estimate it with just a tape measure. This calculator uses the US Navy method, which combines neck, waist and height, plus hip for women. No calipers or bioimpedance scale needed.
What is an ideal body fat percentage?
For health, most men sit well between 10 and 20%, and most women between 18 and 28%. Athletes tend to go below that, but very low levels need supervision.
Is the body fat calculator accurate?
It gives a solid estimate, within 3 to 4 points of tests like DEXA. To track your progress, what matters is repeating the measurement the same way and watching the trend.
What is the difference between body fat and BMI?
BMI only relates weight and height. Body fat percentage shows how much of your weight is actually fat, which BMI cannot separate from muscle.
How often should I measure?
Once a week is enough. Body fat changes slowly, and daily measuring only adds noise.