Phoenix Tracker Pro logoPhoenix Tracker Pro

Body Fat Calculator

Estimate your body fat percentage with the U.S. Navy method — tape measure only.

At navel level, after a normal exhale.

Just below the Adam's apple.

Estimated body fat
17.4%
Fitness
Lean mass (approx)
140 lb
Fat mass (approx)
30 lb

Lean/fat mass assumes a 170 lb reference body. Use the trend over time, not the absolute number.

What this means
Your estimated body fat is 17.4% — in the fitness range. Track this monthly alongside weight for a clearer picture of progress.
Common mistake
Don't chase daily changes. Body fat percentage moves slowly. Measure under the same conditions — same time of day, same tape placement, same hydration — once every 2–4 weeks.
Your next step
Pair this with the calorie deficit calculator to lose fat while protecting the lean mass you have.

This number is just the start

Phoenix Tracker Pro turns your result into a daily plan — photo meal logging, automatic macro math, and weekly streaks.

Why body fat percentage matters more than weight

The scale can't tell the difference between fat, muscle, and water. Two people at the same weight can look and feel completely different depending on their body composition. Body fat percentage helps you focus on the right outcome: less fat, maintained muscle.

How to measure consistently

  • Measure first thing in the morning, before eating or drinking.
  • Use the same tape measure and the same landmarks.
  • Record the number and remeasure every 2–4 weeks.

Frequently asked questions

It's the portion of your total body weight that comes from fat. The rest is lean mass — muscle, bone, organs, and water.

Free tools that pair well with this one.