Generally the way to go about it is like ROI = winnings - losses / investment  investment = (buyin + rake)  losses = (buyin + rake) * (1-winrate)  winnings = (buyin - rake) * (winrate) So in the simple case of $100 games with $5 rake we have: ROI = (95*winrate - 105*(1-winrate))/105 = (200*winrate - 105)/105 And we can flip this equation around to get:105(1 + ROI)/200 = winrate Generalizing: (Buyin w/ Rake)*(1+ROI) / Prizepool = Winrate(Prizepool*Winrate - Buyin w/ Rake) / Buyin w/ Rake = ROI Cliffs:You pay the buyin+rake every game to realize your expected percentage of the entire prizepool (equal to prizepool*winrate). Dividing this by your intial investment (buyin + rake) gives you a return on investment!