Angel rooms are the alternative option to the Devil Rooms which can spawn after defeating a boss. Angel rooms can contain a free item from the angel room pool, spirit hearts or eternal hearts. They have a chance to replace devil rooms if the following 2 conditions are met:
If those two conditions are met, any future devil room doors have a 50% chance to be replaced with an Angel Room instead... however that 50/50 devil/angel split can be weighted differently by doing certain things in the game.
Normally the chance to find an Angel room instead of a Devil Room is 50%, however this can be altered by gaining the following bonuses
In Afterbirth, Key Beggars, Bomb Beggars and Shell Game Beggars do not count for this bonus!
In Afterbirth, donating to a normal/devil beggar until it pays out with an item gives a weak bonus (satisfying Key Beggars, Bomb Beggars and Shell Game Beggars will not work for this bonus).
Players can have a maximum of 2 strong bonuses and 3 weak bonuses on a floor. The combined chances are as follows:
|0 Strong bonuses||1 Strong bonus||2 Strong bonuses|
|0 Weak bonuses||50%||75%||88%|
|1 Weak bonus||63%||81%||91%|
|2 Weak bonuses||72%||86%||93%|
|3 Weak bonuses||86%||89%||95%|
A big thank you to Metarkrai who did the research and added the above stats to the Angel Room Wiki page.