Enter the thermal resistance into the calculator to determine the U-value. This calculator can also evaluate the thermal resistance given the u-value.

W/M2K To U Value Formula

The following formula is used to calculate the U-value from W/m2K.

U = 1 / R


  • U is the U-value (W/m²K) R is the thermal resistance (m²K/W)

To calculate the U-value, take the reciprocal of the thermal resistance. This means dividing 1 by the thermal resistance. The result is the U-value, which measures how well a building element (such as a wall or window) conducts heat. A lower U-value indicates better insulation properties.

What is a W/M2K To U Value?

W/M2K, or watts per square meter per degree Kelvin, is a unit of measurement used in physics to describe the rate of heat flow. The U-value, also known as the overall heat transfer coefficient, is a measure of the rate of heat loss through a structure (such as a wall, floor, or roof). It is expressed in W/M2K and the lower the U-value, the better the material is at insulating. Therefore, converting W/M2K to a U-value essentially involves understanding the insulating properties of a material.

How to Calculate W/M2K To U Value?

The following steps outline how to calculate the U-value (W/m²K) using the formula U = 1 / R.

  1. First, determine the thermal resistance (R) in m²K/W.
  2. Next, use the formula U = 1 / R to calculate the U-value in W/m²K.
  3. Finally, check your answer with the calculator above.

Example Problem:

Use the following variables as an example problem to test your knowledge.

Thermal resistance (R) = 0.05 m²K/W