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.

$39.7 Million  Excalibur Casino, Las Vegas\n\n The largest jackpot on a slot machine at any casino took place at the Excalibur Casino in Las Vegas. Way back in 2003, the winner was a young software engineer who chose to remain anonymous. This gambler from Los Angeles dropped a mere $100 into the slot machine.