Relative Fat Mass Calculator
Estimate body fat percentage from height and waist using the Relative Fat Mass (RFM) formula. No calipers needed.
Independently verified for accuracy
Calculator by Toolsloft ↗- Estimated body fat
- 22.82%
Estimate body fat percentage from just your height and waist measurement using Relative Fat Mass. Enter both in the same unit, whether centimeters or inches, and select your sex. RFM needs no calipers and only two measurements, which makes it easy to repeat.
How this is calculated
Relative Fat Mass uses the ratio of height to waist circumference. Following Woolcott and Bergman (2018), men use 64 minus 20 times height divided by waist, and women use 76 minus 20 times the same ratio. Because it is a ratio, height and waist just need to share the same unit.
How to use
- Select your sex.
- Enter your height and waist in the same unit.
- Read your estimated body fat percentage.
Examples
- Men:
height 175 and waist 85 (same unit) gives about 22.8% - Women:
height 165 and waist 80 gives about 34.8%
FAQ
- Do height and waist need the same unit?
- Yes. RFM uses the ratio of the two, so as long as both are in centimeters or both in inches, the result is the same.
- How accurate is RFM?
- It is an estimate. RFM was designed to track body fat reasonably well from simple measurements, but methods like DEXA are more precise.
- Where do I measure my waist?
- Measure around the abdomen at the level of the navel, standing relaxed after a normal breath out, with the tape snug but not compressing the skin.