RFM Calculator
Calculate Relative Fat Mass (RFM) — a 2018 body-fat estimator that needs only your height and waist.
What is RFM?
Relative Fat Mass was developed in 2018 by Woolcott and Bergman as a simpler, more accurate alternative to BMI for estimating body-fat percentage. It correlates well with DEXA scans and outperforms BMI across diverse populations and ages.
How is it calculated?
RFM = 64 − (20 × height / waist) for men, plus 12 for women. Both height and waist must be in the same unit. Healthy ranges: men 8–25%, women 21–35% depending on age.
Frequently Asked Questions
- Is RFM accurate?
- It correlates with DEXA at r ≈ 0.86, comparable to skinfolds in untrained populations.
- Do I need to weigh myself?
- No, RFM uses only height and waist.
- Best place to measure waist?
- Just above the iliac crest, after a normal exhalation.