Measure the size of the pool. Make sure to include the top rails in your measurements. Some pools have wider top rails that need to be taken into account.
If you have a non-standard pool size like a 12'x19' oval, 15'x28' oval, or 25' round, you’ll need a pool cover that is equal to or greater than the length and width (or diameter, for round pools) values of your pool. So, for a 12'x19' pool, we need a cover made for pools that are at least 12' wide and 19' long. For the round pool example, we'll need a cover meant for a pool greater than 25' in diameter.