Estimate your body fat percentage from height, neck, waist (and hip for women) measurements, and compare it with a BMI-based estimate. Both are rough estimates, not diagnoses.
Body fat percentage is the proportion of your total body weight that is fat, with the rest being muscle, bone, organs and water. It is a more useful measure of fitness than weight or BMI alone, because it separates fat from muscle. Body fat categories differ between organisations and vary with age and fitness level; this calculator uses the categories shown in the table further down this page.
| Method | Body Fat % | Category |
|---|
There are several ways to estimate body fat, from free tape-measure methods to clinical scans. Each trades accuracy for cost and convenience.
| Method | Reliability notes | Cost / Access |
|---|---|---|
| US Navy (tape measure) | Rough estimate; depends heavily on measuring technique | Free — used by this calculator |
| Skinfold calipers | Depends on the tester and the equation used | Low cost, needs technique |
| Bioelectrical impedance (BIA) | Moderate, varies with hydration | Smart scales, gyms |
| DEXA scan | Widely used in clinics and research; still an estimate that varies between machines | Clinic or radiology provider; cost varies |
| Hydrostatic weighing | Used in research and some sports labs; still an estimate | Specialist labs |
This calculator uses the US Navy circumference method — it estimates body fat from your height and a few tape measurements.
Two people can weigh exactly the same but look and perform very differently, because muscle is denser than fat. This is why the scale alone can be misleading.
| Feature | Body Fat | Muscle |
|---|---|---|
| Density | Lower — takes more space | Higher — more compact |
| Effect on metabolism | Burns few calories at rest | Burns more calories at rest |
| On the scale | Same weight, larger size | Same weight, leaner look |
| Health role | Some is essential; excess raises risk | Supports strength and metabolism |
This is also why body fat percentage often tells you more than weight or BMI: it separates fat from the muscle, bone and water that make up the rest of your body.
| Category | Men | Women |
|---|---|---|
| Essential fat | Under 6% | Under 14% |
| Athletes | 6% to under 14% | 14% to under 21% |
| Fitness | 14% to under 18% | 21% to under 25% |
| Average (acceptable) | 18% to under 25% | 25% to under 32% |
| Obese | 25% and above | 32% and above |
US Navy Method: Uses height, neck, and waist (and hip for women) circumference measurements to estimate body fat. It is a rough estimate: results can differ noticeably from other methods such as DEXA, and body shape, measurement technique and hydration all affect the result.
BMI Method: Uses the Deurenberg formula, which estimates body fat from BMI, age, and sex. Because it uses only BMI, age and sex, it cannot distinguish muscle from fat and is likely to be less reliable for athletes and muscular individuals.
The AIHW considers waist circumference a key indicator of abdominal obesity risk. Thresholds: men ≥94 cm (increased risk), ≥102 cm (substantially increased risk); women ≥80 cm (increased risk), ≥88 cm (substantially increased risk).
Dual-energy X-ray absorptiometry (DEXA) is a widely used body composition method, but it is also an estimate: results can vary between machines and with hydration, and it is not error-free. DEXA scans are offered at some Australian radiology clinics and sports medicine facilities; availability, referral requirements and costs vary by provider, so check with the provider.
Body fat percentage is the proportion of your total body weight that is fat tissue, expressed as a percentage. Unlike weight alone, body fat % distinguishes between fat mass and lean mass (muscle, bone, organs, water). Two people with identical weight and height can have vastly different body compositions — and very different health risk profiles.
| Category | Men | Women |
|---|---|---|
| Essential fat | Under 6% | Under 14% |
| Athletes | 6% to under 14% | 14% to under 21% |
| Fitness | 14% to under 18% | 21% to under 25% |
| Average (acceptable) | 18% to under 25% | 25% to under 32% |
| Obese | 25% and above | 32% and above |
These categories follow commonly used American Council on Exercise (ACE) ranges, and the calculator above applies exactly the cut-offs shown here (a result exactly on a boundary falls in the higher category). Different organisations use different categories, and they are a general guide, not a medical diagnosis. What is appropriate for you depends on age, sex, ethnicity and health, so discuss your results with a doctor or accredited practitioner.
Measurement tips: measure waist at the narrowest point (between ribs and hips); neck just below the larynx; hips at the widest point. Take each measurement two or three times and use the average. Enter all values in the same unit system you selected.
The percentage is an estimate of the share of your weight that is fat. The category label (Athletes, Fitness, Average and so on) only tells you which row of the table above the number falls into. It does not diagnose a condition, and it does not say whether your weight is right for you.
If your result is outside what you expected, if your waist measurement is rising, or if you have a health condition, speak to a GP or an accredited practising dietitian or exercise physiologist. This tool is for general education only.
The most useful way to use this calculator is to repeat the same measurements every two to four weeks and watch the direction of the trend. To turn that into a plan, work out your daily energy use with the TDEE calculator, check your waist against height with the waist-to-height ratio calculator, and see how much of your weight is lean mass with the lean body mass calculator.
| Measure | Considers Muscle? | Considers Fat Distribution? | Equipment Needed |
|---|---|---|---|
| BMI | No | No | Scale + height measure |
| Body fat % (circumference) | Partially | Partially | Tape measure |
| Waist circumference | No | Yes (abdominal) | Tape measure |
| DEXA scan | Yes | Yes | Radiology clinic or sports medicine provider |
Hodgdon JA, Beckett MB (1984). Prediction of percent body fat for U.S. Navy men and women from body circumferences and height. Naval Health Research Center reports 84-11 and 84-29.
Deurenberg P, Weststrate JA, Seidell JC (1991). Body mass index as a measure of body fatness: age- and sex-specific prediction formulas. British Journal of Nutrition 65(2):105–114.
Gallagher D et al. (2000). Healthy percentage body fat ranges: an approach for developing guidelines based on body mass index. American Journal of Clinical Nutrition 72(3):694–701.
American Council on Exercise (ACE) body fat categories, as used in the table above.
What is a healthy body fat percentage?
This calculator groups results using commonly used American Council on Exercise (ACE) ranges. For men: under 6% is essential fat, 6% to under 14% athletes, 14% to under 18% fitness, 18% to under 25% average, and 25% or above obese. For women: under 14% is essential fat, 14% to under 21% athletes, 21% to under 25% fitness, 25% to under 32% average, and 32% or above obese. Other organisations use different ranges, and what is healthy for you depends on age, sex, ethnicity and health, so these categories are a general guide, not a diagnosis.
How accurate is the Navy body fat calculator?
The US Navy method is a rough estimate based on height and circumference measurements. Its results can differ from other methods such as DEXA, and the difference varies with body shape, measurement technique and individual characteristics. It is most useful for tracking changes over time using consistent measurements, rather than as an exact number.
What is the most accurate way to measure body fat in Australia?
No single method is error-free. DEXA (dual-energy X-ray absorptiometry), hydrostatic (underwater) weighing and air displacement plethysmography (Bod Pod) are commonly used in clinical and sports settings, but each is still an estimate and results can vary between machines, protocols and hydration status. Availability and costs in Australia vary by provider. For home tracking, using the same method under the same conditions each time is more useful than comparing absolute numbers across methods.
Can I have a healthy BMI but high body fat?
Yes. Someone with low muscle mass can have a BMI in the normal range (18.5 to 24.9) and still carry a relatively high proportion of body fat, and muscular people can have a BMI above 25 with a low body fat percentage. This is a limitation of BMI, which cannot tell fat from muscle. If you are concerned, discuss it with a GP or accredited practitioner.
How do I calculate my body fat percentage?
The easiest free method is the US Navy formula, which uses your height plus waist and neck measurements (and hips for women). Enter these in the calculator above and it estimates your body fat percentage. A professional can also assess body composition using methods such as skinfold measurement or DEXA, although each method has its own limitations.
What is a healthy body fat percentage for men and women?
Body fat categories vary between organisations. This page uses the categories shown in the table above (men: athletes 6% to under 14%, fitness 14% to under 18%, average 18% to under 25%; women: athletes 14% to under 21%, fitness 21% to under 25%, average 25% to under 32%). Women naturally carry more essential fat than men. The range that applies to you depends on age, sex, ethnicity and health, so speak to a doctor or accredited practitioner.
Is body fat percentage better than BMI?
It can be more informative, but neither is a diagnosis. BMI only compares weight with height and cannot tell muscle from fat, so it can misjudge muscular or older people. A body fat estimate tries to separate fat from lean mass, but a tape-measure estimate has its own errors. Using BMI, waist measurement and body fat together gives a fuller picture.
What is the difference between visceral and subcutaneous fat?
Subcutaneous fat sits just under the skin. Visceral fat is stored deeper, around the organs, and is associated with higher health risk. A larger waist measurement can be a sign of more abdominal fat, but a tape measure cannot separate the two types.
How accurate are body fat calculators?
Tape-measure methods like the US Navy formula give a rough estimate and can differ noticeably from methods such as DEXA. Hydration, measurement technique and body shape all affect the result, so track the trend over time rather than fixating on one number.
Does body fat percentage change with age?
Body fat percentage tends to rise with age as muscle mass declines, even if weight stays the same, and some guidelines use different ranges for different ages. The categories used by this calculator are the same for all adult ages, so treat them as a general guide and speak to a health professional about what suits you.
How often should I measure my body fat?
Every two to four weeks is enough to see a real trend without being misled by daily fluctuations. Always measure under the same conditions — same time of day, same hydration, same method — so your readings are comparable.