Relative Fat Mass (RFM) Calculator
Body fat estimate from height and waist only. Free, private and instant.
How to use the Relative Fat Mass
- Pick metric (cm, kg) or imperial (ft, in, lb) units.
- Choose sex: Male or Female.
- Enter height.
- Enter weight (optional) - optional.
- Enter waist circumference.
- Press Calculate to get an instant result with a colour scale, chart and plain-English explanation.
About the Relative Fat Mass
Relative Fat Mass is a newer body fat estimate that needs just height, waist and sex. Research found it can identify excess body fat more accurately than BMI.
Also known as: RFM calculator, relative fat mass index, RFM body fat, waist and height body fat calculator.
Worked example
- Sex: Male
- Height: 170 cm
- Waist circumference: 84 cm
Relative fat mass: 23.5 % (Average). Your estimated body fat is 23.5%, in the "Average" range for men.
- Body fat: 23.5%
- Category: Average
- Height รท waist: 2.02
Formula and cut-offs
RFM = 64 - (20 x height / waist) + (12 x sex), where sex = 0 for men and 1 for women. Height and waist in the same unit.
Frequently asked questions
Is RFM better than BMI?
In the original study RFM estimated whole-body fat percentage more accurately than BMI, with fewer misclassified people, though it is still an estimate.
What RFM is healthy?
The same ranges as body fat percentage apply: roughly 14-24% for men and 21-31% for women is fitness to average.
Where do I measure my waist for RFM?
Measure your waist circumference at the level of your belly button, standing and after breathing out normally. Use the same unit for height and waist.
What is the relative fat mass for a man, 170 cm and a waist circumference of 84 cm?
Relative fat mass: 23.5 % (Average). Your estimated body fat is 23.5%, in the "Average" range for men. Enter your own numbers above for a personal result.
Sources and references
- World Health Organization - Obesity and overweight fact sheet
- WHO - Waist circumference and waist-hip ratio: report of a WHO expert consultation
Written and checked by the MediHub editorial team against the sources above. Read how we build and review our calculators.
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Last updated . This calculator is for education only and is not medical advice. See the medical disclaimer.