Determine the type of sleeping pad you would like. Self-inflating pads are open-cell foam pads that vary in firmness based on your specifications. Backpacking air pads are manually inflated and can be used year-round, while foam pads are simple in style and feature dense foam for insulation. Finally, air mattresses are ideal for car-camping, and imitate the look and feel of an actual bed.
Choose a sleeping pad based on your needs. If you participate in long-distance hiking, a basic, lightweight pad is ideal for its compact size and durability. For backpackers, thicker pads are ideal for comfort, but may take up more space in the backpack. For campers who enjoy the outdoors via car or camper, the size of a sleeping pad is not that important as you are able to transport the pad easily, so larger air mattresses are ideal. For those who camp during winter, REI suggests using two pads: the closed air cell pad with the inflated pad directly on top, to increase insulation from the ground.
Analyze the specifications. Look for a sleeping pad that is at least 72 to 78 inches to make sure you are fully fitting within the pad. Look for pads with at least 20 inches of width, with 25 to 30 if you move around while sleeping. For women, a sleeping pad designed specifically for the woman's body comes in approximately 66 inches with additional padding around the feet and hips for added comfort. Look for a high R-value, which is the amount of insulation within the sleeping pad--1.0 is considered minimal, while 8.0 is well-insulated.
