Body Fat Percentage Calculator
Estimate your body fat percentage using the U.S. Navy circumference method. Enter measurements carefully for the best result.
Note: This tool provides an estimate, not a medical diagnosis. For clinical assessment, consult a healthcare professional.
What is body fat percentage?
Body fat percentage is the proportion of your total body weight that comes from fat mass. Unlike scale weight alone, it gives a clearer picture of body composition and can help you track fitness progress more accurately. Two people can weigh the same but have very different body fat levels, muscle mass, and health profiles.
How this fat percentage calculator works
This calculator uses the U.S. Navy circumference method, a practical formula based on body measurements. It estimates body fat from:
- Height
- Neck circumference
- Waist circumference
- Hip circumference (for women)
The output includes your estimated body fat percentage, category, and (when weight is entered) estimated fat mass and lean body mass.
How to measure correctly
1) Height
Stand barefoot against a wall, with heels and back straight. Measure from floor to the top of your head.
2) Neck circumference
Measure just below the larynx (Adam's apple), with tape level around the neck. Keep tape snug but not tight.
3) Waist circumference
Measure at the navel level (or narrowest waist point if preferred consistently). Relax your abdomen and do not suck in.
4) Hip circumference (women)
Measure at the widest part of the hips/glutes, keeping the tape horizontal and snug.
Understanding your result
A body fat estimate is most useful when tracked over time under the same conditions (same time of day, same hydration status, same tape technique). Daily fluctuations are normal. Focus on trends over several weeks.
- Lower ranges often indicate very lean physiques, common in athletes.
- Middle ranges are often associated with general fitness and health.
- Higher ranges can increase risk for metabolic and cardiovascular issues.
Body fat percentage vs BMI
BMI is useful for population-level screening, but it does not distinguish fat from muscle. Body fat percentage can provide a more personalized perspective, especially for active individuals. For best results, use both along with waist measurements, fitness level, and lab markers if available.
How to reduce body fat safely
Nutrition basics
- Create a moderate calorie deficit, not an extreme one.
- Prioritize protein to support muscle retention.
- Eat mostly whole foods: vegetables, fruit, legumes, lean proteins, and healthy fats.
- Stay hydrated and monitor portion sizes.
Training basics
- Include resistance training 2-4 times per week.
- Add regular walking or low-intensity cardio for consistency.
- Use high-intensity sessions sparingly and recover well.
- Progress slowly and avoid all-or-nothing plans.
Recovery and consistency
Sleep, stress management, and consistency are often underestimated. If your sleep is poor and stress is high, fat loss can stall even when your plan is solid.
Frequently asked questions
Is this calculator accurate?
It is reasonably accurate for many adults, but still an estimate. Hydration, tape placement, and individual body shape can affect results.
How often should I check body fat?
Once every 2-4 weeks is usually enough. Measuring too often can create noise and frustration.
What is a healthy body fat percentage?
Ranges vary by sex, age, and sport. In general, healthy adult ranges are often around 10-20% for men and 18-28% for women, but context matters.
Bottom line
A fat percentage calculator is a practical tool for tracking progress beyond body weight. Use it consistently, combine it with sound training and nutrition habits, and focus on long-term trends. If you have medical concerns or a history of eating disorders, seek guidance from a qualified professional before making major changes.