Health & Fitness
Relative Fat Mass (RFM) Body Fat Estimate
Estimate body fat percentage using the relative fat mass method.
Preparing your result…
What this calculator does
Calculates Body Fat Calculator using the formula verified against the cited source.
What your result means
An estimate from the inputs you enter, within the scope stated below — not advice.
Formula
RFM % = 64 − 20 × height ÷ waist + 12 × sex (0 = men, 1 = women); same length units for height and waist
The step-by-step working for your own numbers appears with the result above and in the PDF report.
Frequently asked questions
Symbols and assumptions
- Inputs
- The values entered in the fields above
- • Correction required. Relative fat mass (RFM) percent=64−20×height/waist+12×sex indicator, with sex=0 for men and 1 for women in the published adult model. Height and waist use the same length units.
Sources and review
Reviewed 2026-10-18 · Next review 2027-04-18
- • Replace ambiguous “sex adjustment” with explicit 0/12 or the indicator convention, avoiding an extra ×12. Name output estimated RFM body fat, not a measured percentage. Follow the study waist-measurement protocol and adult population limits; reject nonpositive dimensions and flag implausible outputs.
Important limitation
This is an educational estimate based only on the values and formula shown. Verify current rates, rules, units, and professional standards before relying on the result. It is not personalized financial or investment advice.
Quick reference
| Scenario | Height (cm) | Waist circumference (at the navel, standing) (cm) | Estimated body fat (RFM) |
|---|---|---|---|
| Worked example | 170 | 85 | 24 % |
| Half the amounts | 120 | 42.5 | 7.5294 % |
| Double the amounts | 220 | 170 | 38.1176 % |
Need the full picture? Get the detailed PDF report with charts, tables, formulas and working steps.
Reviewed 2026-10-18 · Next review 2027-04-18
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