Body Fat Calculator: Estimate Your Body Fat Percentage (Navy Method)
Use this free body fat calculator to estimate your body fat percentage in seconds. It uses the U.S. Navy method (a tape measure is all you need) or the BMI-based method, and tells you your fat category, fat mass, lean mass, and how much weight you could lose to reach a target body fat. Works in imperial (inches, lbs) and metric (cm, kg).
Scale: 0% to 40% body fat. Red = obese, orange = average, yellow = fitness, green = athletes, blue = essential fat.
Body fat categories for your sex
Estimates only. Tape and formula methods can be off by 3-5 percentage points. Use the same method each time to track your trend.
What Is Body Fat Percentage?
Body fat percentage is the share of your total body weight that is made of fat. The rest is lean mass: muscle, bone, organs, water and connective tissue. Unlike the number on the scale or BMI, body fat percentage tells you what your weight is actually made of, which makes it a much better way to track fitness progress.
Two people can weigh the same and look completely different. A person with more muscle and less fat will have a lower body fat percentage and a healthier body composition, even if the scale shows the same number.
How Does the U.S. Navy Body Fat Method Work?
The U.S. Navy method estimates body fat from simple tape measurements, so you do not need calipers, scales or a lab. It was developed by the Navy to check service members' body composition, and it is one of the most popular home methods.
Women: BF% = 495 / (1.29579 - 0.35004 x log10(waist + hip - neck) + 0.22100 x log10(height)) - 450
All measurements are in centimeters in the formula. This calculator converts inches for you.
How to Measure Correctly
- Neck: measure just below the larynx (Adam's apple), with the tape sloping slightly downward toward the front. Do not flare your neck.
- Waist: men measure at the navel. Women measure at the narrowest point of the waist. Relax your stomach and measure after a normal exhale.
- Hip (women only): measure around the widest part of the hips and buttocks.
- Tips: measure in the morning, keep the tape snug but not tight, take each measurement 2-3 times and use the average.
The BMI Method
If you do not have a tape measure, the calculator can also estimate body fat from your BMI, age and sex using a well-known adult formula:
(sex = 1 for men, 0 for women)
This is less accurate, especially for muscular people, because BMI cannot tell muscle from fat. Use the Navy method whenever possible.
Body Fat Percentage Chart
| 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 |
Women naturally carry more essential body fat than men because of hormones and reproductive needs. Ideal ranges also rise slightly with age, so a slightly higher number can be perfectly healthy for people over 40.
How Accurate Are Body Fat Calculators?
No home method is perfect. Here is how the common options compare:
| Method | Typical accuracy | Notes |
|---|---|---|
| DEXA scan | Very good | Gold standard in practice, costs money and needs a clinic |
| U.S. Navy (tape) | Roughly within 3-5 points | Free, simple and good for tracking trends |
| Skinfold calipers | Within 3-5 points with a skilled tester | Depends heavily on technique |
| Smart scales (BIA) | Varies widely | Affected by hydration and meal timing |
| BMI formula | Rough estimate | Misleading for very muscular or very small people |
The most useful approach is to measure under the same conditions every 2-4 weeks and watch the trend, not any single number.
How to Lower Your Body Fat Percentage
- Eat in a moderate calorie deficit of about 10-20% below maintenance. Use the calorie deficit calculator to find your number.
- Prioritize protein (about 1.6-2.2 g per kg of body weight) to protect muscle while losing fat.
- Lift weights 2-4 times per week. Strength training preserves and builds muscle, which improves body composition.
- Walk daily. 7,000-10,000 steps adds easy calorie burn without extra fatigue.
- Sleep 7-9 hours and manage stress. Both strongly affect hunger, recovery and fat storage.
- Be patient. Losing about 0.5-1% of body weight per week is a realistic, sustainable pace.
Frequently Asked Questions About Body Fat
What is a healthy body fat percentage?
For men, about 10-20% is generally considered healthy. For women, about 18-28%. The exact healthy range varies with age and fitness level.
How accurate is the Navy body fat calculator?
It is usually within about 3-5 percentage points of more advanced methods such as DEXA. It is great for tracking progress over time when you measure the same way each time.
What body fat percentage shows abs?
Most men see clear abdominal definition around 10-14%, and most women around 16-20%. Genetics affect where you store fat, so it varies from person to person.
Is BMI or body fat better?
Body fat is generally more informative because it separates fat from muscle. BMI only uses height and weight, so it can mislabel muscular people as overweight.
How often should I measure my body fat?
Every 2-4 weeks is enough. Measuring more often only captures day-to-day noise from water and food.
Can women have a body fat percentage as low as men?
No. Women need more essential fat for hormonal and reproductive health. Dropping below about 14% can disrupt menstrual cycles and bone health for many women.
Why is my body fat different on different calculators?
Each method uses different formulas and assumptions, and hydration also affects some tools. Stick to one method and compare your results over time.
Disclaimer: This calculator is for educational purposes only and is not medical advice. Consult a doctor or registered dietitian for a full health assessment, especially if you are pregnant, under 18, or have a medical condition.
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