How to Convert an RSI to an RValue
Rvalues provide a means for quantifying the thermal resistance of an insulating material. If the Rvalue is high, the material is a good thermal insulator, and heat will not easily flow through it. If the Rvalue is low, the material is a poor insulator.
RSI stands for RValue SystÃ¨me Internationale, and it also measures thermal resistance but does so using the metric system. Converting one to the other requires some simple math.

Multiply the RSI by 6 to calculate a rough estimate of the Rvalue. For example, if the RSI is 2, multiply 2 by 6 to get the Rvalue of 12.

Divide the original RSI value by 0.176. This will calculate the Rvalue more accurately. For example, if the RSI is 2, calculate 2 / 0.176 to get the Rvalue of 11.36.

Take the Rvalue you just found and multiply it by 0.176 to verify that you performed the calculation correctly. This should result in the original RSI value. For example, if you calculated an Rvalue of 11.36, multiply 11.36 by 0.176 to get the original RSI value of 2.
Tip
The units of RSI are squaremeter kelvins per watt. The units of Rvalue are Fahrenheit squarefoot hours per British thermal unit.