The typical backyard trampoline has a round 14' diameter frame. In general, the larger the trampoline, the more room that is available for bouncing. However, bouncing with multiple jumpers is not recommended, even for large trampolines. Smaller trampolines will fit more easily in backyards with less space, but adult trampolines are typically 12' or greater in diameter. Trampolines higher than 20" above the ground are not recommended for children less than 6 years of age, and there are many trampolines 8' diameter and smaller that meet this requirement.