The RTP is based on many spins, called the slot cycle. The game maker sets the cycle, which is the number of spins needed to reach the rate. Every slot has a different cycle, but it’s typically a huge number, like tens of thousands. For instance, if the best RTP online slots have an RTP of 96% and a cycle of 45,000 spins, it should reach the payout by the 45,000th spin.