Body Fat Percentage Calculator
Estimate body fat percentage with the U.S. Navy tape method, then see lean mass, fat mass, BMI, and target weight.
Body Fat Percentage Calculator
Units
Profile
Used to choose the Navy circumference equation.
Tape measurements
Use a soft tape, stand relaxed, and keep the tape level.
Goal readout
This tool estimates body composition from tape measurements. It is useful for trends, not diagnosis.
How to use the body fat calculator
Choose your units, enter your height and weight, then add the tape measurements for your sex. Men need neck and waist. Women need neck, waist, and hips. The calculator converts metric inputs behind the scenes because the Navy equations use inches.
The most important part is consistency. Measure at the same time of day, use the same tape position, and keep the tape snug without pulling it into the skin.
What the Navy method measures
The Navy tape method estimates body density from circumference measurements and height. It is popular because it is quick, cheap, and repeatable, but it is still an estimate. Small changes in tape placement can move the result by a few points.
For challenge tracking, use the number as one signal alongside weight, progress photos, workout consistency, and how your clothes fit.
Body fat percentage vs BMI
BMI is a weight-for-height screening number. It is fast, but it does not know the difference between fat mass and lean mass. Body fat percentage gives a more direct body-composition estimate, especially if you lift, train often, or are changing shape without a large scale change.
Using your result in a challenge
During a 75-day challenge, remeasure every 2 to 4 weeks instead of every day. Reset75 can help you keep the daily behaviors steady while you track slower changes with weigh-ins and progress photos. Download Reset75 when you want the full challenge log on your phone.
Frequently Asked Questions
Common questions about body fat percentage calculator
What is the Navy body fat method?
The Navy method estimates body fat from height and tape measurements. Men enter neck and waist. Women enter neck, waist, and hips. It is practical for home tracking because it uses a tape measure instead of lab equipment.
How accurate is this body fat calculator?
Treat it as an estimate. Tape-based formulas can be useful for trend tracking, but hydration, posture, tape placement, and body shape can change the result. Use the same measuring process each time.
Where should I measure my waist?
Measure at the same spot each time with the tape level and snug, not pulled tight. Many Navy-style instructions use the narrowest point for men and the natural waist for women, but consistency matters most for personal trend tracking.
Do women need to enter hip circumference?
Yes. The female Navy equation uses neck, waist, hip, and height. The hip input is hidden for male calculations because that equation does not use it.
Is body fat percentage better than BMI?
They answer different questions. BMI is a quick weight-for-height screening number. Body fat percentage estimates body composition, so it can be more helpful when you are tracking fat loss, muscle gain, or visible progress.
What body fat percentage is healthy?
Healthy ranges depend on sex, age, training history, and medical context. This calculator uses common fitness categories for a quick label, but it should not replace advice from a clinician or coach.
Can I use this during a 75-day challenge?
Yes. Remeasuring every 2 to 4 weeks works better than checking daily. Pair this number with weigh-ins and progress photos in Reset75 so you can see the trend instead of reacting to one measurement.
How often should I remeasure body fat?
Every 2 to 4 weeks is enough for most people. Tape measurements move slowly, and daily checks can make normal water and posture changes look more meaningful than they are.