Formula
- Use the units shown beside each field.
- Results update automatically whenever you change an input.
- Displayed values use up to four decimal places, or scientific notation for very small or large numbers. Calculations use standard floating-point arithmetic; exact integer and fraction tools identify their own precision rules.
- Single homogeneous layer; surface films, framing and air leakage are not included. Layer conductance is not necessarily the wall U-value.
Example Calculation
- Thickness: 100 mm
- Conductivity: 0.04 W/(m·K)
100 mm at conductivity 0.04 gives R=2.5 m²·K/W.
Frequently asked questions
How do I use this calculator?
Enter thickness, conductivity. The result updates automatically. Use Reset to restore the example values.
What method does it use?
R=thickness meters/conductivity; layer conductance=1/R.. Single homogeneous layer; surface films, framing and air leakage are not included. Layer conductance is not necessarily the wall U-value.
Why might a rounded result differ?
The calculation keeps full numeric precision internally, then rounds the displayed result. Rounding intermediate steps by hand can produce a slightly different answer.
Are my inputs saved online?
No. This calculator processes your inputs in your browser. A recently used list stores only calculator names on this device, not your entered values.
Check the assumptions and units before using this result. Read about calculation methods.