R-Value vs RSI Explained
R-value and RSI both describe thermal resistance, but they use different unit systems. The important point for purchasing is to use the rating stated for the product and the target required by your project specification.
Conversion
RSI ≈ R-value × 0.1761. R-value ≈ RSI × 5.678.
Do not treat conversion as design advice
Converting the number does not tell you which thermal target your wall, roof or floor requires. Regulations, assemblies and project specifications determine that separately.
Use the converter
R-Value / RSI Converter converts known reference values without recommending a target.