Body Fat Calculator
Estimate body fat % using circumference measurements.
⚖️ US Navy method using circumference. Less accurate than DEXA scans but a practical at-home estimate.
What Is This Tool?
This calculator estimates body fat percentage using the US Navy method, which uses circumference measurements of your neck, waist, and (for women) hips. It's a practical at-home alternative to expensive body composition scans.
How to Measure
- Neck: Just below the larynx, keeping tape level
- Waist: At the navel (men) or narrowest point (women)
- Hip: Widest point around buttocks (women only)
- Measure in the morning, before eating, for consistency
Body Fat Categories
- Essential fat: 2-5% men / 10-13% women (minimum for survival)
- Athlete: 6-13% men / 14-20% women
- Fitness: 14-17% men / 21-24% women
- Average: 18-24% men / 25-31% women
- High: 25%+ men / 32%+ women
Why Body Fat Beats BMI
BMI cannot distinguish muscle from fat. A muscular athlete and an overweight person can have the same BMI but very different body fat percentages and health risks. Body fat is the more meaningful metric — though harder to measure precisely.
Frequently Asked Questions
How accurate is the Navy method?
It has an error range of about ±3-4% compared to DEXA scans. It works best for people near average body composition. For very lean or very muscular people, other methods (calipers, DEXA, hydrostatic) are more accurate.
About the Body Fat Calculator
The Body Fat Calculator lets you figure out body fat calculatorinstantly, without reaching for a spreadsheet or doing the math by hand. Whether you're planning a budget, checking a loan, or working through homework, the tool applies the correct formula behind the scenes and shows the result the moment you enter your numbers.
Unlike a static chart or table, this calculator adapts to your exact inputs. You can adjust any value and see the outcome update in real time, which makes it easy to compare scenarios — for example, "what if the rate were 1% lower?" or "what if I paid an extra $50 a month?"
How to Use This Tool
- Enter the main values the calculator asks for (for example, amount, rate, and time).
- Pick the right unit or option where the tool offers a choice.
- Read the result, which appears instantly below the inputs.
- Adjust any field to test a different scenario — the answer updates without a reload.
- Copy or note the result. Nothing is stored, so close the tab when you're done.
Why Use an Online Calculator?
Browser-based tools like this one have a few real advantages over installed software or manual methods:
- No installation. It opens instantly in any browser, on any operating system.
- Private by default. Everything runs locally, so your data stays on your device.
- Always up to date.There's nothing to update — you always get the latest version when you load the page.
- Free and unlimited. Use it as often as you like, with no account and no caps.
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