Measure the size of the pool. Make certain to include the step section in your measurements if they extend past the pool. A standard in ground winter cover comes rectangular in shape. Record your measurements in a note pad.
Take into consideration how low you plan to drop the water level. Most pool covers will come with enough material to compensate for a water level that is reduced up to 12". If you need to drain the water level more than that, you will need to purchase a larger cover.
Keep in mind that if you have a step section the extends past the pool, you will need a winter cover large enough to cover it. The winter cover can't be cut to the shape of the pool. If you need a winter cover that follows the shape of the pool, you will need to purchase a safety pool cover.
You will also want to take into consideration any obstacles along the pool's perimeter that can't be removed such as ladders, rails and water features. Since the cover can't be cut, the cover will need to be large enough to go around these items.
Once you have received your new winter cover, carefully remove it from the box and measure it to ensure it is the correct size. If it is incorrect, please contact the dealer you purchased the cover from for further instruction.