Calculate heat shrink tubing recovered size from supplied diameter and shrink ratio, or estimate the suggested tube size for an object diameter.

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Diameters are inside diameters. Ratio gives a nominal free-recovery estimate; verify the product’s expanded minimum, recovered maximum, tolerances and installation instructions.

Heat Shrink Size Formula

The following formula is used to estimate the recovered (after shrinking) size of heat-shrink tubing from its as-supplied size and shrink ratio.

NS = OS × (Y) / (X)
  • Where NS is the new (recovered) size
  • OS is the original (as-supplied) size
  • X:Y is the heat shrink ratio of the tubing (for example 2:1, 3:1, or 4:1), as specified by the manufacturer (X is the as-supplied dimension and Y is the recovered dimension)

To calculate the recovered size from heat-shrink tubing, multiply the as-supplied size by Y/X (for common ratios like 2:1 where Y = 1, this is the same as dividing by X).

Heat Shrink Size Definition

Heat shrink size typically refers to the size (often the diameter) of heat-shrink tubing either as supplied (before heating) or recovered (after heating). The shrink ratio describes how the tubing’s size changes from as-supplied to recovered.

Heat Shrink Size Example

How to calculate a heat shrink size?

  1. First, determine the original size.

    Measure the as-supplied size of the heat-shrink tube (before heating).

  2. Next, determine the heat shrink ratio.

    This is the manufacturer-specified ratio of the tubing’s as-supplied size to its recovered size after heat is applied (for example, 2:1).

  3. Finally, calculate the heat shrink size.

    Calculate the recovered size of the heat shrink tubing using the equation above.

FAQ

What is a normal heat shrink ratio?

Common heat-shrink tubing ratios are typically 2:1 or 3:1, with higher ratios (such as 4:1 or 6:1) also available depending on the product.