M+QuickMedCalc
Educational reference only. Not a diagnostic tool. See full disclaimer.
GeneralRelative Fat Mass

Relative Fat Mass (RFM) Calculator

Estimate adult relative fat mass from height, waist circumference, and sex.

Content updated: View sources

cm

Estimated relative fat mass

—

Anthropometric estimate; not a direct body-fat measurement

Equation used: — · Height — cm · Waist — cm

About

Relative fat mass (RFM) is an adult anthropometric estimate developed from height, waist circumference, and sex in a US population sample and validated against DXA in the original study. It estimates whole-body fat percentage but is not a direct body-composition measurement.

Formula

Male RFM (%) = 64 − 20 × height ÷ waist circumference
Female RFM (%) = 76 − 20 × height ÷ waist circumference
Height and waist must use the same unit

Interpretation

Measurement: Use the same unit for height and waist. In the original study, waist circumference followed NHANES measurement procedures at the uppermost lateral border of the ilium.

Worked example: For a male with height 175 cm and waist 90 cm, RFM = 64 − 20 × 175 ÷ 90 = 25.1%.

Limitations: RFM is a population-derived estimate. Measurement technique and applicability across age, pregnancy, athletic body composition, ethnicity, and clinical conditions can affect accuracy. It does not replace DXA or another direct body-composition method.

References

  1. Woolcott OO, Bergman RN. Relative fat mass (RFM) as a new estimator of whole-body fat percentage. Sci Rep. 2018;8:10980.
  2. CDC/NCHS. National Health and Nutrition Examination Survey Anthropometry Procedures Manual.

FAQ

Related Calculators

BMI

Calculate Body Mass Index from weight and height.

IBW

Calculate ideal body weight using the Devine formula.

HOMA-IR

Calculate the HOMA1-IR index from fasting insulin and fasting glucose.

Disclaimer

Educational and informational reference only. Not intended to replace professional medical advice, diagnosis, treatment, or independent verification.