Estimate your body fat using simple measurements and see where you stand
What's next?
A single measurement tells you where you are - tracking over time shows where you're heading. SatisFIT logs your body metrics alongside your training so you can connect the dots. Try SatisFIT free
This calculator uses the US Navy circumference method, which estimates body fat based on measurements of the neck, waist, and (for women) hip. It's one of the most accessible methods requiring only a tape measure. The formula was developed by the US Navy for fitness assessments and correlates well with more expensive methods like DEXA scans for most body types.
Waist: Measure at the narrowest point, typically at the navel level. Neck: Measure just below the larynx (Adam's apple). Hip (women): Measure at the widest point of the buttocks. All measurements should be taken while standing relaxed. Use a flexible tape measure pulled snug but not compressing the skin. Measure at the same time of day for consistency.
This calculator is useful for anyone who wants a quick body fat estimate without expensive equipment. It's particularly helpful for people tracking fat loss progress over time, as the method is consistent and repeatable. If you already know your body fat percentage, you can use the Fat-Free Mass Index (FFMI) Calculator to see how your lean mass compares to your genetic potential. For a simpler weight screening, try the Body Mass Index (BMI) Calculator.
The biggest mistake is inconsistent measurement technique. Small differences in tape placement can shift results by 1-2%. Always measure at the exact same spots and have someone else help if possible. Another common error is measuring after a meal or workout when the waist may be temporarily bloated. Measure first thing in the morning on an empty stomach for the most accurate baseline. Finally, do not compare circumference-based estimates directly to results from DEXA or hydrostatic weighing, as each method has its own margin of error.
For men, 14-17% is considered the fitness range and 18-24% is average. For women, 21-24% is fitness and 25-31% is average. Athletes typically carry less: 6-13% for men and 14-20% for women. Essential fat minimums are around 3-5% for men and 10-13% for women.
The US Navy method typically has a margin of error of 3-4% compared to DEXA scans. It tends to be most accurate for people in the average body fat range and less accurate at very low or very high body fat levels. Its main strength is consistency - it tracks changes reliably over time.
BMI uses only height and weight, so it cannot distinguish between muscle and fat. Body fat percentage directly estimates how much of your weight is fat tissue. Two people with the same BMI can have very different body fat levels depending on their muscle mass.
Every 2-4 weeks is ideal if you are actively trying to change your body composition. More frequent measurements add noise without useful signal. Always measure under the same conditions (morning, fasted, relaxed) to get comparable results.