How to Measure Tubing

Regardless of what project you need tubing for, there are a few things you need to know and do before you make your purchase.

Measure Tubing

  1. Think about what you need the tubing for. If it is to enclose something, you will need to know the total exterior diameter of the item(s) to be enclosed. If it will be placed inside something, you will need to know the interior diameter of the item that will encase the tubing.

  2. Measure the interior or exterior diameter of the item(s) the tubing will be used with. The diameter is the distance, straight across the middle, of a circle. Write down this measurement.

  3. Measure the length of the item(s) the tubing will be used with in order to determine the length of the tubing you will need. Write down this measurement.

  4. Use the recorded measurements to determine how much tubing you will need, as well as the size (diameter) you will need.

  5. Buy or cut the appropriate amount and type of tubing.

  6. Tip

    Not all manufacturers measure the diameter of tubing in the same way. Some measure the tubing after it is flattened. The industry standard is to measure the tubing's interior diameter. Be sure to carefully read the packaging before purchase so you know you are getting the correct size of tubing. If the tubing is exposed, measure it yourself. If it is not, ask a store clerk if they will open the package so you can verify the diameter if you are concerned. If you are using the tubing for wires or cords, be sure to bundle the wires or cords first for easier handling and encasing in the tubing.


    When selecting tubing, bear in mind that there are many different types of tubing to choose from and not all types will be appropriate for your project. If your project may be subject to heat or cold, be sure to buy tubing that can withstand the temperature it to which it will be exposed. Think very carefully about what your tubing will be used for and everything it might be exposed to in order to prevent any possible fire or other safety hazards.