Estimate body fat percentage using standard body measurements (US Navy formula).
The Body Fat Percentage calculator offers an accessible way to estimate the proportion of fat mass relative to total body weight. Utilizing the 'US Navy Method,' this tool requires only a few simple tape measurements of the neck, waist, and hips (for females). Understanding body fat percentage is often more informative than weight alone, as it provides insight into body composition and helps differentiate between lean muscle and adipose tissue.
This calculator is designed for adults who want to track their fitness progress or assess their health risks more accurately than a standard BMI calculation. While a certain amount of fat is essential for hormone production and vitamin storage, excess body fat can be associated with increased risks for metabolic and cardiovascular conditions. This tool is provided for educational purposes to help you monitor trends in your body composition. It does not diagnose obesity or any medical condition and should be used alongside other health metrics and professional medical consultations.
Type in your own measurements — the grey hints are just examples.
Measure at the narrowest point of your neck.
Measure at the navel level (males) or narrowest point (females).
Required for females. Measure at the widest point.
To use the calculator, start by selecting your biological sex, as the formulas for fat distribution differ between males and females. Enter your height and the required circumference measurements: Neck (at the narrowest point), Waist (at the navel for males, or the narrowest point for females), and Hip (at the widest point, required for females only). You can use either centimetres or inches by toggling the unit system. For the most accurate results, use a flexible, non-elastic measuring tape and ensure it is level and snug against the skin without compressing it. Take all measurements while standing upright and after a normal exhale.
Your result is an estimate of your total body fat percentage, categorized into ranges such as 'Athletic,' 'Fitness,' or 'Acceptable.' These categories are based on general health guidelines and vary by sex. For instance, females naturally require a higher percentage of essential fat for reproductive health and hormonal balance. A result in the 'Athletic' or 'Fitness' range generally suggests a higher proportion of lean mass, while values in the 'Overweight' or 'Obese' ranges may indicate an increased association with certain health risks.
It is important to remember that the US Navy Method is an estimation tool with a typical margin of error of about 3–4% compared to clinical standards like DEXA scans or hydrostatic weighing. It is highly dependent on precise measurement technique; even a small error in tape placement can lead to a significant percentage shift. Factors such as individual bone structure, muscle distribution (hypertrophy), and even hydration levels or recent meals can influence the circumference measurements and the final result.
Furthermore, this method cannot distinguish between visceral fat (fat stored around internal organs) and subcutaneous fat (fat stored just under the skin). Visceral fat is more closely linked to metabolic and cardiovascular health risks, making it a critical marker that simple tape measurements might not fully capture. It also does not account for age-related changes in body composition, such as sarcopenia (muscle loss) in older adults, which can lead to an underestimation of fat percentage.
Because this is not a diagnostic tool, you should not use it as the sole basis for major health or dietary decisions. We recommend tracking your results over time to see trends rather than focusing on a single measurement, as trends are more indicative of progress than one-off data points. Discuss your body composition goals and these estimates with a healthcare professional or a certified fitness expert. They may recommend additional metrics like waist-to-height ratio or skinfold calipers to create a more balanced and accurate approach to your health and wellness journey.
Related Health Calculators
Learn More
Body fat percentage reflects the proportion of total body mass made up of fat tissue, as opposed to lean mass including muscle, bone, and organs. Unlike BMI, which uses only height and weight, body fat percentage estimates provide context about body composition — an important distinction when two people of similar weight may have very different health profiles.
Healthy body fat ranges differ by sex and age. For adult men, values between approximately 10–20% are generally considered healthy, while 20–25% may be acceptable for older men. For adult women, healthy ranges typically fall between 20–30%. Values above these thresholds can be associated with increased cardiometabolic risk, while very low values may indicate inadequate fat reserves.
Formula-based body fat estimates (such as those using BMI or waist circumference) carry significant error margins compared to clinical measurements like DEXA scanning or hydrostatic weighing. Results from this calculator should be treated as a broad indication rather than an accurate measurement of body composition.
Explore further with Healio360
If you have concerns about body composition, metabolic health, or unexplained weight changes, consult a healthcare professional or registered dietitian.
Sources & Methodology
These references support the formula, educational ranges, and interpretation used in this calculator. Results are estimates and are not a diagnosis.
Medical Disclaimer
This calculator and its accompanying content are provided for general educational and informational purposes only. They are not intended to be, and should not be used as, a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of a qualified healthcare provider with any questions you may have regarding a medical condition or before making decisions about your health. Never disregard professional medical advice or delay seeking it because of information provided by this tool. Healio360 does not warrant the accuracy, completeness, or usefulness of this content and assumes no liability for actions taken based on it.