For most round above-ground pools , a 4 ft x 8 ft pool pillow is the safest all-around choice, especially for pools around 24 to 33 ft wide. For smaller round pools, a 4 ft x 4 ft pillow is usually enough, and for oval pools, people often use 4 ft x 15 ft or multiple pillows.

Quick sizing guide

Pool type Common pillow size
12 ft to 18 ft round 4 ft x 4 ft
24 ft to 33 ft round 4 ft x 8 ft
Oval pools 4 ft x 15 ft or multiple smaller pillows
These sizes are consistent with pool supplier sizing guides and winterizing recommendations.

How to choose

  • Pick a pillow that fits under the cover without crowding it.
  • Use a larger pillow or multiple pillows if your pool is big or you want better support across the centerline.
  • If your area gets freezing weather, a pillow is recommended to help absorb ice expansion and reduce stress on the pool walls and cover.

Simple rule

If you’re unsure, go with 4 x 8 for a standard round pool, and 4 x 4 only for smaller round pools. If you want, I can help you pick the exact size for your pool diameter.