Comparing two slots, the slot with the higher RTP will pay back more money in prizes. For example, a slot with a 96% RTP will pay back £96 in every £100 wagered. A slot with a 90% RTP will pay back £90 in every £100 wagered. However, keep in mind that these numbers are not absolute. They are averages and your experience of a game will change from one day to the next.