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Body Fat Calculator: Navy Method & CUN-BAE | Free
Calculate your body fat percentage with the US Navy method or CUN-BAE equation. See ACE category, fat mass and lean mass. Free, instant results.
Medically reviewed by Dr. Ivan IbáñezNº Col. 17/05487Mar 10, 2026
CalcVita. (2026). Body Fat Calculator: Navy Method & CUN-BAE | Free. CalcVita. Retrieved October 16, 2026, from https://calcvita.com/en/calculators/body-fat
Suggested article
Body Fat Percentage: Why It Matters More Than BMI
Understand why body fat percentage is a better health marker than BMI, how the Navy and CUN-BAE methods work, and what the ACE categories mean for your fitness.
Read the full article →How does this calculator work?
This calculator estimates your body fat percentage using two validated methods: the US Navy circumference method and CUN-BAE. Both provide an ACE classification and break down fat mass vs. lean mass.
US Navy method
Developed by Hodgdon and Beckett (1984) for the US Department of Defense. It requires tape measurements of neck and waist circumference for men, plus hip circumference for women. The formula uses logarithmic relationships between circumferences and height to estimate body density and fat percentage, with an accuracy of ±3–4 % vs. hydrostatic weighing.
CUN-BAE method
The Clínica Universidad de Navarra–Body Adiposity Estimator (Gómez-Ambrosí et al., 2012) uses your BMI, age and sex to estimate body fat without tape measurements. Validated in 6,510 subjects against air-displacement plethysmography with r=0.89. Ideal when circumference data is not available.
ACE body fat classification
The American Council on Exercise (ACE) provides these reference ranges:
| Category | Men | Women |
|---|---|---|
| Essential fat | 2–5 % | 10–13 % |
| Athletes | 6–13 % | 14–20 % |
| Fitness | 14–17 % | 21–24 % |
| Average | 18–24 % | 25–31 % |
| Obese | 25 %+ | 32 %+ |
Body fat vs BMI
A 2025 study in Annals of Family Medicine (Mainous et al., NHANES) followed US adults aged 20–49 for 15 years: a high body fat percentage was associated with a 78% higher risk of all-cause mortality (adjusted HR 1.78), whereas BMI showed no significant association. Unlike BMI, body fat percentage differentiates between muscle and adipose tissue, making it more clinically relevant for individuals who are muscular or have atypical body compositions.
How to measure correctly
- Neck: measure just below the larynx (Adam’s apple), tape sloping slightly downward at the front. Keep the tape snug but not compressing the skin.
- Waist: men measure horizontally at navel level; women at the narrowest point of the torso (natural waist). Stand relaxed, exhale normally, and keep the tape horizontal.
- Hip (women only): measure at the widest point of the buttocks. Keep feet together and the tape horizontal all around.
Sources
- Hodgdon JA, Beckett MB. Prediction of percent body fat for U.S. Navy men from body circumferences and height. Naval Health Research Center Report No. 84-11, 1984.
- Hodgdon JA, Beckett MB. Prediction of percent body fat for U.S. Navy women from body circumferences and height. Naval Health Research Center Report No. 84-29, 1984.
- Gómez-Ambrosí J et al. Clinical usefulness of a new equation for estimating body fat. Diabetes Care 2012;35(2):383-388. PMID: 22179957
- American Council on Exercise (ACE) – Percent Body Fat Calculator: general body fat percentage categories (archived 2023)
- Mainous AG 3rd et al. Body Mass Index vs Body Fat Percentage as a Predictor of Mortality in Adults Aged 20-49 Years. Ann Fam Med 2025;23(4):337-343. PMID: 40555527
Frequently asked questions
- How accurate is the Navy body fat method?
- The US Navy method (Hodgdon-Beckett 1984) has an accuracy of ±3–4% compared to hydrostatic weighing. It’s the most practical field method validated by the Department of Defense.
- What is the CUN-BAE method?
- CUN-BAE (Clínica Universidad de Navarra–Body Adiposity Estimator) uses your BMI, age and sex to estimate body fat. Published in Diabetes Care 2012, validated in 6,510 subjects with a correlation of r=0.89.
- Is body fat percentage better than BMI?
- Often, yes. A 2025 study in Annals of Family Medicine (Mainous et al.) followed US adults aged 20–49 for 15 years: a high body fat percentage was associated with a 78% higher risk of death from any cause (adjusted HR 1.78), while BMI showed no significant association. BF% accounts for the difference between muscle and fat mass.
- What is a healthy body fat percentage?
- According to ACE guidelines: Men 14–17% (fitness), Women 21–24% (fitness). Athletes range 6–13% (men) and 14–20% (women). Essential fat minimums are 2–5% (men) and 10–13% (women).
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