Enter the current size of the tube or object and the heat shrink ratio into the calculator to determine the heat shrink size.

Heat Shrink Size Formula

The following formula is used to calculate a heat shrink size.

  • Where NS is the new size
  • OS is the original size
  • HSR is the heat shrink ratio (usually 2:1 or 3:1) this is determined by the thermal expansion of the material

To calculate the new size from heat shrink, divide the original size by the heat shrink ratio.

Heat Shrink Size Definition

A heat shrink size is a size at which an object constricts to after being exposed to heat, hence the name heat shrink.

Heat Shrink Size Example

How to calculate a heat shrink size?

  1. First, determine the original size.

    Measure the original size of the tube or object.

  2. Next, determine the heat shrink ratio.

    This is the ratio of the original size to new size after hat is applied.

  3. Finally, calculate the heat shrink size.

    Calculate the new size of the heat shrink using the equation above.


What is a normal heat shrink ratio?

A normal heat shrink ratio is typically 2:1 or 3:1 for many materials.