Body Fat Calculator | Estimate Your Body Fat Percentage
Use this free body fat calculator to estimate your body fat percentage, total fat mass, and lean mass using the U.S. Navy circumference method. Enter your measurements for a result accurate to within 3 to 4 percentage points with no lab equipment required.
Your Stats
Enter your weight, height, waist, and neck measurements to estimate your body fat.
What Is Body Fat Percentage?
Your body fat percentage is the proportion of your total body weight that comes from fat tissue. The remainder is lean mass: muscle, bone, organs, connective tissue, and water. Two people at the same scale weight can carry very different amounts of fat and look entirely different, which is why body fat percentage is a far better indicator of fitness and health than weight alone.
A small amount of fat is biologically essential. Your body requires it for hormone synthesis, brain function, thermal insulation, and absorption of fat-soluble vitamins. Too little fat is as medically serious as too much. This calculator uses the U.S. Navy circumference method, validated against hydrostatic weighing, to estimate body fat from simple tape measurements. If you know your body fat percentage, enter it into the BMR Calculator for a more precise metabolic rate estimate.
Men 3 to 5 percent, women 10 to 13 percent. This is the minimum required for organ protection, hormone production, and neurological function. Dropping below these levels is a medical concern.
Men 6 to 13 percent, women 14 to 20 percent. Typical for competitive athletes who train consistently and eat to support performance while maintaining low body fat.
Men 14 to 17 percent, women 21 to 24 percent. Common among recreational exercisers who train regularly and eat a reasonably structured diet without extreme restriction.
Men 18 to 24 percent, women 25 to 31 percent. Typical for healthy adults who are not specifically training or dieting. Above 25 percent for men and 32 percent for women is classified as obese.
How Does the Body Fat Calculator Work?
The calculator applies the U.S. Navy circumference formula to your measurements and returns body fat percentage alongside fat mass and lean mass in three steps.
- Measure
- Formula
- Result
Take Your Body Measurements
What Factors Affect Your Body Fat Percentage?
Body fat is shaped by far more than calorie intake alone. These are the main variables that drive it up or down.
Calorie Balance
Eating more than your TDEE adds body fat over time. Eating less burns it. Calorie balance is the dominant driver of body fat changes and no other factor overrides it. The rate at which you gain or lose fat is determined by the size and consistency of your calorie surplus or deficit across weeks and months.
Resistance Training
Lifting weights builds the lean muscle mass that defines a low body fat appearance and protects lean tissue when calories are reduced. Two people at the same body fat percentage can look very different depending on how much muscle underlies the fat, which is why resistance training changes the visual outcome of fat loss so dramatically.
Age and Biological Sex
Women require more essential fat than men for reproductive and hormonal health, which is reflected in the higher reference ranges across all categories. Both sexes tend to accumulate fat and lose muscle with age without consistent resistance training, raising body fat percentage even when total body weight stays the same.
Genetics and Fat Distribution
Where your body stores fat first and loses it last is largely determined by genetics. Some people accumulate fat primarily around the abdomen, others in the hips and thighs. The total amount of fat you carry at any given calorie intake is shaped by both genetics and behavior, but behavior is the larger variable in practice.
Sleep and Stress
Chronic poor sleep raises cortisol and ghrelin, both of which promote fat storage and increase appetite at the same calorie intake. Research consistently shows that people sleeping fewer than 6 hours per night lose more muscle and less fat during the same calorie deficit compared to those sleeping 7 to 9 hours.
Hormones and Metabolic Health
Thyroid function, insulin sensitivity, and life-stage hormones all influence how readily the body stores or releases fat. Hypothyroidism, insulin resistance, and hormonal imbalances from high cortisol or low testosterone can make fat loss significantly slower without any obvious change in calories or exercise. A doctor can rule these out if progress has stalled.
How Do You Use Your Body Fat Result?
Your body fat percentage tells you what kind of change to pursue, not just whether the scale number should go up or down.
Reduce Body Fat
A consistent calorie deficit of 300 to 500 calories per day combined with resistance training and adequate protein is the direct path to lower body fat. Track your body fat percentage monthly alongside scale weight so you know whether you are losing fat or muscle. Use the Calorie Deficit Calculator to find the right daily calorie target for a sustainable pace of fat loss.
Improve Body Composition
Body recomposition, reducing fat while maintaining or gaining muscle, produces the biggest visual change for the same change in scale weight. It requires protein at 1.6 to 2.2 grams per kilogram, consistent resistance training, and calories at or slightly below maintenance. Use the Macro Calculator to set the right protein, carbohydrate, and fat targets for your recomposition phase.
Track Progress Accurately
Scale weight alone cannot tell you whether you are losing fat or muscle. Taking body fat measurements every 4 weeks alongside weekly weight averages shows whether your training and nutrition are moving in the right direction. Pair this calculator with the BMR Calculator to see how changes in your lean mass are affecting your resting metabolic rate over time.
What Are the Best Ways to Lower Your Body Fat?
Six evidence-based habits that reduce body fat while protecting the lean mass that defines how you look and feel.
- 1
Create a 300 to 500 calorie daily deficit through food first
rather than relying on exercise to create the gap, since diet changes are more reliable and do not carry the recovery cost of added cardio on top of resistance training
- 2
Hit 1.6 to 2.2 grams of protein per kilogram of body weight every day
because adequate protein is the single most important factor in determining how much of the weight you lose comes from fat versus muscle during a calorie deficit
- 3
Lift weights at least 2 to 3 times per week throughout the fat loss phase
because resistance training sends the signal to your body to retain muscle even when calories are reduced, which is what makes the visual result of fat loss worth the effort
- 4
Measure body fat every 4 weeks using the same technique each time
because the trend over months is the data that matters, not any single reading, and consistent measurement protocol is what makes the comparison valid
- 5
Sleep 7 to 9 hours per night consistently
because poor sleep independently increases hunger, reduces workout performance, and shifts the composition of weight loss toward muscle rather than fat even at the same calorie deficit
- 6
Set realistic long-term targets before starting
because going from 25 to 20 percent body fat is straightforward over 3 to 4 months, while going from 12 to 8 percent can take twice as long and requires much stricter adherence to achieve
Frequently Asked Questions About Body Fat
Quick answers to the questions people ask most.
For men, 10 to 20 percent is generally considered healthy, with competitive athletes typically sitting between 6 and 13 percent. For women, 18 to 28 percent is healthy, with athletes between 14 and 20 percent. Falling below essential fat levels, which is roughly 3 to 5 percent for men and 10 to 13 percent for women, creates serious health risks regardless of how you look or feel.
Related Calculators
Click any calculator to get the full picture of your body composition.
Calculate total daily burn at your current composition.
See how lean mass affects your resting metabolic rate.
Set a deficit to reduce body fat at a safe pace.
Set protein targets to protect lean mass while cutting.
Compare BMI to body fat for a fuller health picture.
Set a target weight to pair with a body fat goal.