Insulation R-Value Calculator

Calculate total R-value for a multi-layer wall, floor, or roof assembly by adding up individual layer R-values. Also computes U-value. Runs locally in your browser.

Layer 1 R-value

m²·K/W or ft²·°F·h/BTU

Layer 2 R-value

m²·K/W or ft²·°F·h/BTU

Layer 3 R-value

m²·K/W or ft²·°F·h/BTU

Layer 4 R-value

m²·K/W or ft²·°F·h/BTU

Layer 5 R-value

m²·K/W or ft²·°F·h/BTU

Layer 6 R-value

m²·K/W or ft²·°F·h/BTU

Enter R-values for each layer (leave blank or 0 for unused layers).

All calculations run locally in your browser — nothing leaves your device.