R-Value Insulation Table: R-value by Material thickness
Reference table of r-value for R-Value Insulation across a range of material thickness values — exact, engine-computed figures you can read off at a glance.
R-Value Insulation Calculator
Verified formula Updated Jun 2026 Private — runs on your device
Verified formula
Private
R-value
2.5000
For general information only — not financial, tax, legal or medical advice. Verify before you rely on it.
How to use the R-Value Insulation Calculator
The R-Value Insulation Calculator works out your r-value in an instant. Enter material thickness and thermal conductivity (k) and the result updates as you type — it is free, needs no sign-up, and runs entirely in your browser so your figures stay private.
- Enter the material thickness.
- Enter the thermal conductivity (k).
- Read off your r-value — the calculator updates automatically, with no button to press.
Formula
The R-Value Insulation Calculator uses the formula:
R-value = Material thickness ÷ Thermal conductivity (k)
Worked example
For example, with material thickness of 0.1 m and thermal conductivity (k) of 0.04 W/m·K, the r-value is 2.5000.
| Material thickness | 0.1 m |
|---|---|
| Thermal conductivity (k) | 0.04 W/m·K |
| R-value | 2.5000 |
|---|
Results are estimates for educational use, not professional advice.
Frequently asked questions
Divide thickness by thermal conductivity. A 0.1 m layer with k of 0.04 has an R-value of 2.5 m²K/W.
It measures resistance to heat flow; a higher R-value means better insulation.
R-values of layers add up, so multiple layers give a higher total resistance.
It depends on climate and the element. Walls, roofs and floors each have recommended targets.
Enter the material thickness. Enter the thermal conductivity (k). Read off your r-value — the calculator updates automatically, with no button to press.
Related guides
How to Calculate R-Value Insulation: Formula, Steps & Examples
Learn how to calculate R-Value Insulation — the formula explained step by step, with worked examples and a free calculator to check your answer.