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Body Fat Calculator

Estimate body fat percentage with the classic US Navy circumference (tape) method or a BMI + age estimate. Works for men and women in metric or imperial—calculations stay in your browser.

Fitness screening estimate only—not a medical measurement or official Navy BCA. Technique and landmarks affect results; DEXA or clinical assessment is more precise.

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By Muhammad Abdullah Rauf · Founder, EverydayTools.proUpdated 2026-09-06· Reviewed by EverydayTools Editorial Team

What is body fat percentage?

Body fat percentage describes body composition—not just scale weight. Two people can weigh the same and have very different fat-to-lean ratios.

**This body fat calculator estimates body fat % two ways:**

1. **Classic US Navy circumference method** — height plus waist and neck (and hips for women), measured with a soft tape.

2. **BMI + age method** — height, weight, age, and sex when you do not have girth measurements.

Results include an estimated body fat %, a fitness-oriented category band, and (when weight is entered) estimated fat mass and lean mass. Calculations run in your browser.

This is a **fitness screening estimate**, not a clinical measurement, DEXA scan, or the official 2026 Navy Body Composition Assessment (BCA).

Estimate body fat percentage at home with a tape measure (Navy method) or BMI + age—then track trends monthly with the same technique.

When to use this calculator

Home fitness tracking

Estimate body fat without calipers

Use a soft tape measure and the Navy-style method for repeatable monthly check-ins.

Men and women

Sex-specific inputs and ranges

Women include hip circumference; category bands differ by sex.

No tape available

Quick BMI + age estimate

Fallback method when you only know height, weight, age, and sex.

Fitness planning

Classic Navy-style tape estimate

Useful for general body-composition tracking—not official military BCA pass/fail.

Body fat percentage chart (ACE reference)

General adult reference bands from the American Council on Exercise (ACE). Not a diagnosis; ranges vary by source and population.

CategoryMenWomen
Essential fat2–5%10–13%
Athletes6–13%14–20%
Fitness14–17%21–24%
Average18–24%25–31%
Obese (ACE label)25%+32%+

Source: ACE body composition categories (commonly republished; e.g. Healthline ACE chart summary). The on-tool scale uses similar bands and labels the highest band “Above average” for softer screening language.

US Navy method vs BMI body fat estimate

FactorNavy circumferenceBMI + age
InputsHeight, waist, neck, hips (women)Height, weight, age, sex
EquipmentSoft tape measureScale + height
Best forHome composition trackingQuick estimate without girths
Muscular buildsOften more useful than BMI aloneMay overestimate fat
Official 2026 Navy BCANot the same processNot used

Body fat % vs BMI

Body fat %BMI
What it usesComposition estimate (method-dependent)Height and weight only
Muscular athletesCan stay low while weight is highOften reads “overweight”
This siteBody Fat CalculatorBMI Calculator

Common mistakes to avoid

Treating the result as official Navy BCA compliance

This is a classic circumference estimate for fitness tracking—not the 2026 official BCA process.

Using the wrong waist landmark

Men (classic): navel level. Women (classic): natural/narrowest waist. Measure after a normal exhale.

Comparing one reading to DEXA as if identical

Expect differences across methods. Track monthly trends with the same protocol.

Troubleshooting

No result in Navy mode

Likely cause: Missing hip for women, waist ≤ neck, or invalid numbers.

Fix: Complete required fields; waist must be larger than neck.

Big week-to-week swings

Likely cause: Inconsistent landmarks, posture, hydration, or timing.

Fix: Measure monthly, same time of day, same landmarks.

How to use this body fat calculator

  1. Choose US Navy or BMI method

    Select US Navy if you can measure waist and neck (and hips for women). Choose BMI method if you only have height, weight, and age.

  2. Select metric or imperial units

    Use kg/cm or lb/in. Switch units anytime—the tool converts displayed values.

  3. Enter sex and measurements

    Pick male or female. For Navy mode, enter height, waist, and neck; women also enter hips. Weight improves fat/lean mass estimates.

  4. Read body fat %, category, fat mass, and lean mass

    Results update as you type. Use the category chart as general fitness context—not a diagnosis.

  5. Optional: continue to lean body mass or calories

    Open the Lean Body Mass Calculator with your body fat % when you want LBM planning numbers.

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Frequently asked questions

What is a healthy body fat percentage?

Reference charts such as the American Council on Exercise (ACE) list general adult bands: for men, fitness often around 14–17% and average 18–24%; for women, fitness often 21–24% and average 25–31%. Essential fat is lower (about 2–5% men, 10–13% women). Ranges vary by source, age, and population—use them as context, not a diagnosis.

How do I calculate my body fat percentage?

With this calculator: enter sex and either (1) Navy-style height, waist, neck, and hips for women, or (2) height, weight, and age for the BMI method. You can also compute Navy formulas manually with logarithms, but the tool applies them automatically.

How accurate is the US Navy body fat calculator?

It is an estimate. Results can differ from DEXA and other lab methods. Tape placement, posture, and day-to-day variation affect readings. Use the same technique monthly for trends. It is not a clinical diagnostic measurement.

How do I measure waist and neck for the Navy method?

Neck: just below the larynx, tape level, head relaxed. Waist (men, classic Navy-style): at navel level after a normal exhale. Waist (women, classic Navy-style): at the natural/narrowest waist. Hips (women): widest point of hips/buttocks. Soft tape, snug without compressing skin; average two readings.

Can I calculate body fat without calipers?

Yes. The US Navy-style method uses a tape measure (waist, neck, height, and hips for women). The BMI + age method needs no tape—only height, weight, age, and sex.

What is the difference between BMI and body fat percentage?

BMI uses only height and weight. Body fat percentage estimates composition (fat vs lean). Muscular people can have a high BMI with relatively low body fat—body fat % is often more useful for fitness tracking.

Does the calculator work for men and women?

Yes. Select male or female. Women must enter hip circumference for the Navy method. Category reference bands also differ by sex.

Can I use pounds and inches?

Yes. Switch to imperial (lb/in). Enter height as feet and inches when that mode is selected.

Can I use kilograms and centimeters?

Yes. Metric (kg/cm) is available—enter height in centimeters and circumferences in cm.

Is this the official 2026 Navy BCA calculator?

No. This tool uses a classic Navy-style circumference (Hodgdon-style) estimate for fitness tracking. It is not the official 2026 Navy Body Composition Assessment pass/fail process (which uses updated WHtR screening and official Navy tables). Do not use it to determine military compliance.

What is the Navy body fat formula?

Classic metric form: BF% = 495 ÷ denominator − 450. For men, the denominator uses log₁₀(waist − neck) and log₁₀(height). For women, it uses log₁₀(waist + hip − neck) and log₁₀(height). Imperial published forms use different coefficients with inch measurements; this calculator converts to the metric equations internally.

Does this calculator upload my measurements?

Core calculations run in your browser. Height, weight, and girths are not uploaded to EverydayTools servers for normal use. Optional local save uses device storage only.

How do I get lean body mass from my result?

This page shows estimated lean mass when weight is entered. For dedicated LBM formulas and planning, use the Lean Body Mass Calculator with your body fat %.

Privacy, accuracy, and trust

Privacy

Waist, neck, hip, height, and weight are processed in your browser for core estimates and are not uploaded to EverydayTools servers.

Accuracy

Screening estimate only. Results can differ from DEXA and other methods. Measurement technique strongly affects tape-based estimates.

Fitness screening estimate only—not medical advice, diagnosis, or official military Body Composition Assessment. Consult a healthcare provider for health decisions.

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Reviewed by EverydayTools Editorial Team on 2026-09-06.

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