For every 100 games you play, you have paid 4 buyins worth of rake. If the games were at $10, that means you've paid $40. If you win 52 games, your record after 100 games is 52-48 aka you've won 4 more games than you've lost.
5% rake would be 52.5% to breakeven
6% rake would be 53%
10% is breakeven at 55%.
The easiest method is to calculate how much each chip is worth as a percentage. Let's say the stake for a heads-up sit-and-go (HUSNG) game is $10, plus a rake of $0.40. Don't be confused by the $10 stake including the rake; it actually means that the stake is $9.60 plus $0.40 in rake, which makes the total percentage of rake 4.166666666666667%.
If the format is hyper with 500 starting chips, then 5 chips represent 1%. Therefore, if you make an expected value (EV) of 21 chips per game, you are theoretically beating the break-even point with an ROI of 0.2%. The break-even point would be 20 chips EV per game (500/100*4).