It’s impossible to know exactly how many kids you’re going to have at the party. Especially when it comes to last minute guests bringing siblings. Nate’s birthday prices are for parties with 20 kids or less. There is an additional $5 charge for each additional child. It’s not a problem and the total number of kids can be quickly counted at the end of the party before paying the fee. Don’t worry, adults, infants, and sleeping babies do not count. :-)