Pool Liner Thickness

27 or 20 mil: Which Pool Liner Thickness Should You Choose?

Oftentimes people ask us which liner material is “better:” the 20 mil or the 27 mil?

In reality, there is no “better” liner.  The most important choice is not the thickness of the material, but the liner pattern that you choose. Liners fail for two reasons.  The ink fades or the material dry rots above the waterline.  Thicker material solves neither of these problems.

Choose the vinyl liner pattern that you like the best.  If it comes in 27 mil at no extra charge, take it, but don’t pay extra for it.  You shouldn’t pass on your first pattern choice just to get the thicker material.  In our opinion, there is no meaningful advantage to thicker material.  There is no difference in wear, durability, longevity or warranty. You are going to be looking at that pattern in your backyard for at least the next seven years.  Ultimately, the pattern you choose should outweigh the thickness of your liner material.  It is what you think looks the best that matters.

View all of our available 27 mil and 20 mil patterns here.

What does 20 mil mean?

When it’s time to replace the liner in your pool, you will most likely hear the term mil as it relates to the thickness of a liner.

A mil is a unit of measurement that is equal to one thousandth of an inch. Therefore, a 20 mil liner is equal to 20 thousandths of an inch and a 27 mil liner is equal to 27 thousandths of an inch. If you have a one inch tall stack of liner samples, there would be 50 20 mil pieces. By the same token, there would only be 37 27 mil samples in an inch tall stack of samples.

A good frame of reference is five standard sheets of copy paper are as thick as a 20 mil liner. A mil, however, is not the same unit of measure as a millimeter.

Even though it’s thicker, a 27 mil liner will not last any longer than a 20 mil liner. For more information about the durability of a liner, please click here and here.

McDougall pattern


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