Dear Melissa, The max user limit is determined based on the amount of space given for each user. While the inflatable is rated for a capacity of 100 lbs each, and 400 lbs total, the amount of space available is enough for about 5 kids. If each user weighs 100 lbs exactly, the limit would be 4 users, but if you have a scenario where each user is 80 lbs or less, there is enough space for up to 5 users to bounce safely. I hope that helps! Please feel free to explore our FAQ for more information: http://www.blastzone.com/why-is-the-gross-weight-higher-than-max-users Sincerely, Blast Zone Support