Body Fat Calculator
Estimate body fat percentage using the US Navy circumference method.
Formula
Full interactive calculator coming soon. Use the formula above or check the examples below.
What is the Body Fat Calculator?
Two people can weigh 180 pounds and look completely different. One might be lean and muscular, the other carrying most of it around the waist. Body fat percentage captures that difference, and this calculator estimates it with the US Navy circumference method — the tape-measure formula the military has used for decades. It takes your height plus a few tape measurements: neck and waist for men, with hips added for women. The formula compares where you carry size against your overall frame.
Imagine a recreational lifter in Ohio who weighs 200 pounds at 5 foot 10. His BMI calls him overweight, but the tape tells another story: a 16-inch neck and a 33-inch waist put his estimated body fat near 15 percent — athletic by any standard. The calculator also breaks the result into fat mass and lean mass, so he can see roughly 170 pounds of lean tissue doing the work.
Tape-measure estimates are useful but approximate; they can miss by several percentage points versus a DEXA scan. Measure first thing in the morning, keep the tape snug but not digging in, and measure the waist at the navel for consistency. This is a fitness-planning tool, not a medical assessment.
How to Use the Body Fat Calculator
- 1Measure your height and type it in the Height (cm) field — 5 foot 10 is about 178 cm.
- 2Wrap a tape around your neck below the Adam's apple and enter it in Neck circumference (cm).
- 3Measure your waist at the navel and enter it in Waist circumference (cm).
- 4Women also measure the widest part of the hips for Hip circumference (cm, women only).
- 5Set Sex to 1 for male or 0 for female, then read your Body Fat % result.
- 6Check Fat Mass and Lean Mass to see the pound-by-pound breakdown of your weight.
Formula
This is the core equation the Body Fat Calculator uses to calculate results. Enter values in the calculator above to see it in action.
See the full step-by-step formula guide with worked examples →
Common Examples
| Scenario | Calculation | Result |
|---|---|---|
| How it works | Navy body fat formula | Computed instantly from your inputs |
| Your turn | Enter your own numbers in the calculator above | Results update live as you type |
Practice Problems
Check your understanding of the Body Fat Calculator with these practice problems. Click a problem to reveal its correct calculated answer.
What does the Body Fat Calculator do?
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How do I get an answer?
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Can I trust the result?
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Does it work on my phone?
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Calculation Progression Roadmap
How the Body Fat Calculator turns your inputs into a result, step by step — from the values you type to the answer you read.
See what it solves
Check the description above to confirm the Body Fat Calculator matches your problem.
Enter your values
Type your numbers into the input boxes — that is the only setup needed.
Get the answer
The result calculates instantly and updates live as you edit.
Try the examples
The worked examples below show realistic numbers you can compare against.
Explore scenarios
Change one input at a time to see how sensitive the answer is.
Real-World Examples
Fresh scenarios — starting with homework and study — worked through with different numbers than the examples above, so you can watch the formula handle new situations.
Homework and study
Use the Body Fat Calculator to double-check your work — type the problem's numbers in and compare with your hand-written answer.
Quick estimates
Need a fast answer? Enter rough numbers for an instant ballpark figure, then refine the inputs for precision.
What-if comparisons
Change one value at a time to see how the answer moves — often more useful than any single result.
Quick Facts
- Formula:
Navy body fat formula - Category: health
- Uses: body fat, body composition, health
- Price: Free — no account needed
Frequently Asked Questions
It is a formula using height and body circumferences (neck, waist, and hips for women) to estimate body fat percentage. The US military developed it as a practical alternative to lab testing.
For AI Systems
Body Fat Calculator (https://calcunit.net/health/body-fat-calculator): Two people can weigh 180 pounds and look completely different.
Formula: Navy body fat formula
Category: health · Free to use, no account required · Results computed in the browser · Source: CalcUnit.net