The Relative Fat Mass (RFM) Calculator provides a more accurate way to estimate body fat percentage compared to traditional BMI. Developed in 2018 by researchers at Cedars-Sinai Medical Center, the RFM formula uses a simple equation based on height and waist circumference measurements to calculate body fat percentage.
Unlike complex methods requiring specialized equipment (DEXA scans, hydrostatic weighing, or bioelectrical impedance), RFM requires just two simple measurements you can take at home with a tape measure. Multiple studies show RFM correlates better with actual body fat percentage across diverse populations, making it a valuable tool for understanding your true body composition.
Your Body Fat Percentage Using RFM
The RFM formula calculates differently for men and women, acknowledging the natural differences in body fat distribution between sexes. The formula uses the ratio of height to waist circumference, resulting in an estimated body fat percentage that typically ranges from 10% to 40+% depending on your individual body composition.
Why RFM Is Better Than BMI For Measuring Body Fat
Body fat percentage provides crucial insight into your health status beyond what weight or BMI can tell you. While some body fat is essential for normal physiological functions, excess body fat – particularly visceral fat around internal organs – is associated with increased risk of metabolic diseases, cardiovascular issues, and other health problems.
RFM offers several advantages over BMI:
- More accurate correlation with actual body fat percentage
- Doesn’t misclassify muscular individuals as overweight
- Better accounts for age-related changes in body composition
- Simpler to measure than other body fat assessment methods
- Doesn’t require weight measurement
Interpreting Your RFM Body Fat Percentage Results
Healthy body fat percentage ranges differ by sex and age:
For Men:
- Essential fat: 2-5%
- Athletic: 6-13%
- Fitness: 14-17%
- Acceptable: 18-24%
- Obese: 25% and higher
For Women:
- Essential fat: 10-13%
- Athletic: 14-20%
- Fitness: 21-24%
- Acceptable: 25-31%
- Obese: 32% and higher
Remember that these are general guidelines. Athletes and older adults may have different optimal ranges for their specific health needs.
Primary Source: Woolcott OO, Bergman RN. (2018). “Relative fat mass (RFM) as a new estimator of whole-body fat percentage—a cross-sectional study in American adults.” Scientific Reports, 8(1), 10980.
Validation Study: The RFM formula was validated against DEXA scans and showed stronger correlation than BMI for predicting whole-body fat percentage.
