Relative Fat Mass (RFM) Calculator

cm
cm
Health Updated 14 Jun 2026

Relative Fat Mass (RFM) Calculator is a health and wellness calculator that helps you calculate relative fat mass (rfm) values from your input data. The formula used is: RFM = 64 − (20 × height ÷ waist) + (12 if female). Enter values using the units shown next to each input field (e.g. kg, cm, years).

  • Height and waist entered in the same unit (cm).

Formula

RFM = 64 − (20 × height ÷ waist) + (12 if female)
  • Relative Fat Mass (RFM) Calculator gives you a fast estimate using your inputs and updates instantly when you change any value.
  • Formula: RFM = 64 − (20 × height ÷ waist) + (12 if female)
  • Input definitions: • Height: the numeric height used in the calculation • Waist: the numeric waist used in the calculation
  • Manual method: write down each input, apply the formula step by step, then compare your manual result with the calculator output.
  • Enter values using the units shown next to each input field (e.g. kg, cm, years).
  • This calculator uses widely accepted health formulas and returns screening estimates only. It does not replace a diagnosis from a qualified healthcare professional.
  • Compare your result with published reference ranges. Values outside the normal range warrant a conversation with your doctor.
  • Practical tip: test a low, medium, and high scenario to understand sensitivity before making decisions.

Example Calculation

Inputs
  • Height: 170 cm
  • Waist: 85 cm

Suppose you enter: Height = 170, Waist = 85. The calculator applies the formula (RFM = 64 − (20 × height ÷ waist) + (12 if female)) and shows all output values below. Change any input field to immediately see how the result changes.

Frequently asked questions

What is the Relative Fat Mass (RFM)?
The Relative Fat Mass (RFM) Calculator is a health and wellness calculator that helps you calculate relative fat mass (rfm) values from your input data. Enter values using the units shown next to each input field (e.g. kg, cm, years).
When should I use this calculator?
Use this calculator whenever you need a quick, accurate result for relative fat mass (rfm) values from your input data without working through the arithmetic manually.
What units should I enter?
Enter values using the units shown next to each input field (e.g. kg, cm, years).
How accurate are the results?
This calculator uses widely accepted health formulas and returns screening estimates only. It does not replace a diagnosis from a qualified healthcare professional.
How do I interpret the result?
Compare your result with published reference ranges. Values outside the normal range warrant a conversation with your doctor.
How can I verify the calculation manually?
Use the displayed formula and work through the numbers step by step. If your manual result differs slightly, check rounding and unit conversions first.
Can I use this for planning and budgeting?
Yes. Run best-case, expected, and worst-case inputs to compare outcomes and make safer planning decisions.

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