Body Fat Calculator
🇦🇺 Australia version
Australian scales and tape measures are metric, and this body fat calculator opens that way. Enter neck, waist and height in centimetres, plus hips if you select Female, and it estimates body fat with the US Navy equation, names a category and quotes a range for your age. It is an estimate, so a GP can say what it means for you.
Use Body Fat Calculator online
Body Fat Calculator
Calculate your body fat percentage using the US Navy method
Personal Information
Body Measurements (cm)
Australia rules and figures
- Kilograms and centimetres are the everyday units on the Australian page, so Metric is the starting Unit System and no conversion is needed for most tape measures.
- The Department of Health reads BMI with WHO cut-offs: Healthy weight is 18.5 to 24.9, Overweight starts at 25 and Obesity class 1 at 30.
- Department of Health advice is that a healthy BMI tends to sit lower for Asian background and higher for Polynesian background, with no figures attached.
- Adult categories do not apply under 18, and the Department notes BMI is less accurate for teenagers, so treat results for young people with caution.
Sources: Australian Government Department of Health: BMI and waist measurement (checked 2026-11-08)
How the body fat calculator works
Neck, waist and hip go into the Navy equation as centimetres, and weight in kilograms feeds only the BMI shown alongside.
Women: 495 ÷ (1.29579 − 0.35004 × log10(waist + hip − neck) + 0.22100 × log10(height)) − 450. The men's version drops hip and uses 1.0324, 0.19077 and 0.15456
- Unit System opens on Metric on the Australian page. A change to Imperial relabels the boxes in pounds and inches and stays selected.
- Men aged under 30 see 6-14% as their range, those in their 30s see 11-17%, and men from 50 see 16-22%.
- The percentage is floored at zero and shown to one decimal place, and the BMI beside it is weight divided by height in metres squared.
- Enter height in centimetres only. A person who knows their height as feet and inches must convert it before typing.
How to use the body fat calculator
- Select gender. Choose Male or Female. The hip box is needed only for Female.
- Confirm the unit system. The page should show Metric. If you change it to Imperial, every label switches to pounds and inches.
- Enter your age and tape readings. Age is optional. Neck and waist are required, and hip as well for women, all in centimetres.
- Read the category tables. The Categories tab shows the men's and women's bands so you can see where the result falls.
- Read the measuring guide. The Guide tab explains where to hold the tape and suggests measuring more than once.
Example: 182 cm man and 168 cm woman
A man of 45 who is 182 cm and 88 kg, with a 39 neck and 90 waist, sees 18.8%, the Average label, a 14-20% range and BMI 26.6. Enter age 28, 168 cm, 64 kg, neck 33, waist 80 and hip 100 for a woman, and the page shows 31.1%, Average again, a 14-21% range and BMI 22.7.
When to use the body fat calculator
- Looking beyond the scales. Compare the body fat estimate with BMI to see whether weight alone tells the full story.
- Seeing how waist affects the result. Change only the waist box and watch the percentage and category respond.
- Bringing numbers to a check-up. Take the estimate, the category and the BMI to a GP and ask how to read them.
What the body fat calculator does not do
- The estimate comes from a formula using three or four tape readings, not from a scan.
- Category cut-offs and age ranges are fixed in the code and are not taken from Australian Government guidance.
- The Department gives no body fat thresholds for any ethnic background, so none is applied.
- Results below the essential-fat band are shown as calculated. They are not a recommendation, and a GP should advise.
When something else is a better fit
- When you want to log tape readings by date and compare them, use the Body Measurement Tracker, which stores dated entries.
- When you want a weight category from the Department of Health bands, use the BMI Calculator.
- When you need a measured value, or advice about your health, use a GP, who can refer you for a DEXA scan if one is useful.
Questions about the body fat calculator
Does Australia have its own body fat categories?
Not on this page. The categories and age ranges are fixed in the calculator and come from the Navy method's usual bands. The Department of Health publishes BMI bands, which appear as a separate figure.
What if my waist is smaller than my neck?
For men the page then shows a message instead of a percentage, because the logarithm needs waist minus neck above zero. Re-measure both and keep the tape level.
Do I need to enter my weight?
Yes, the page asks for it before showing any result, but it only affects the BMI. Your body fat percentage stays the same if you change the weight and keep the other measurements.
Which measurements are in centimetres?
On Metric, height, neck, waist and hip are all centimetres and weight is kilograms. That keeps every box in the units a standard Australian tape measure and scale show.