The Ugga Bugga slot machine game has the highest payout percentage, at 99.07%. The second highest is Mega Joker by NetEnt, with a 99% RTP. Jackpot 6000 by NetEnt and Uncharted Seas by Thunderkick come in second and third, with RTPs of 98.8% and 98.6%, respectively.

Has anyone ever won big on online slots? Yes, online slots have created quite a few millionaires over the years. Some games can have progressive jackpots worth millions of dollars and it only takes one lucky spin to win the entire amount.