Body Fat Calculator

⚕️ Not medical advice. This is general information for healthy adults and does not replace a doctor, dietitian or other health professional. Speak to one before acting on a result, especially if you are pregnant, have a medical condition or are worried about a symptom.

Why body fat % matters more than body weight

Two people can weigh the same yet have very different body compositions. A person with 15% body fat and 85% lean mass tends to have a lower metabolic health risk than someone with 30% body fat at the same weight. Body fat percentage can give a fuller picture of health risk, fitness level, and the effectiveness of diet and exercise programmes.

US Navy method vs BMI method

The US Navy formula requires circumference measurements and is generally more accurate. The BMI-based Deurenberg formula needs only weight, height, age, and sex — it is less accurate but useful when you cannot take body measurements. Use the Navy method whenever possible.

How to reduce body fat healthily

Maintain a moderate calorie deficit (300–500 kcal/day) — extreme restriction tends to lose muscle mass too.
Prioritise protein (1.6–2.2 g/kg of body weight) to preserve lean mass during a cut.
Include resistance training 3–4 days per week to maintain or build muscle while losing fat.
Aim for 0.5–1% of body weight loss per week — faster rates are more likely to cost lean mass.

Body fat percentage categories

The American Council on Exercise (ACE) defines these ranges for adults:

Essential fat: Men 2–5%, Women 10–13% — minimum for organ protection
Athletes: Men 6–13%, Women 14–20%
Fitness: Men 14–17%, Women 21–24%
Acceptable: Men 18–24%, Women 25–31%
Obese: Men 25%+, Women 32%+

Note that body fat percentage does not tell the full story — visceral fat (fat around organs) is generally associated with greater health risk than subcutaneous fat (under the skin) at the same total body fat percentage. A waist circumference above 90 cm for men or 80 cm for women (commonly used cut-offs for Asian adults) is associated with elevated visceral fat risk regardless of overall body fat percentage.

Limitations of body fat estimation

Formula-based estimates can carry an error margin of ±3–5%. More accurate methods — DEXA scan, hydrostatic weighing, and Bod Pod — generally require clinical equipment. For tracking progress over time, consistency matters more than absolute accuracy: use the same method, same time of day, and same conditions each measurement to make meaningful comparisons.

Frequently asked questions

How is body fat percentage calculated?

This calculator offers two methods. The US Navy formula uses circumference measurements (waist, neck, and hip for women) along with height to estimate body fat using a logarithmic formula. The BMI-based Deurenberg formula uses BMI, age, and sex. Both are estimates — a DEXA scan is generally considered a more accurate reference.

What is a healthy body fat percentage?

For men: 6–13% (athletes), 14–17% (fitness), 18–24% (acceptable). For women: 14–20% (athletes), 21–24% (fitness), 25–31% (acceptable). Going below essential fat levels (men under 2%, women under 10%) can be dangerous. Higher body fat (the ACE 'obese' category starts at about 25% for men and 32% for women) is associated with increased health risks.

How do I measure my waist accurately?

For the US Navy formula, measure your waist at the navel level while exhaling normally. Do not suck in or push out. Measure neck at the narrowest point, just below the Adam's apple. Women measure hips at the widest point across the buttocks.

How accurate is the US Navy formula?

The US Navy method can have an error of roughly ±3–4% compared to hydrostatic weighing. It gives a reasonable estimate for many people and is widely used by the military and fitness professionals. It may be less accurate for very muscular individuals or those with unusual body proportions.

What is lean body mass?

Lean body mass (LBM) is everything in your body except fat — muscles, bones, organs, water, and connective tissue. It is calculated as: LBM = Total Weight × (1 − body fat%). Increasing LBM through strength training tends to raise your metabolic rate somewhat and can improve body composition even without losing weight.