The amount of progress you make towards levelling up in each room is random, with the figures calibrated so that a full run generally gets you to Level 11 in a Campaign (30 room worlds), Castle (20 rooms), Tournament (20 rooms) or Daily Event (20 rooms) run, but it can rarely get to 12
On 12 room worlds (Space Station, Vile Temple and the Weekend Boss Run) you usually (always?) get 12, but I don’t recall getting 13.
Because of the random nature, even without Fast Learner you can’t predict in which room exactly you will get each perk - so when Fast Learner gives a bonus on the progress, it’s not easy to predict how many extra perks it will give you
Still trying to figure out how it works after the 1.11 buff, provisionally this is what I have:
| When taken | Number of Perks (Before 1.11) | After 1.11 |
|---|---|---|
| Starting Perk | 13 guaranteed, rarely 14 | 14 guaranteed, rarely 15 |
| Level 2 | 12 guaranteed, 13 almost certain | 14 guaranteed |
| Level 3 | 12 guaranteed, sometimes 13 | Prediction: 13 guaranteed, sometimes 14 |
| Level 4 | 12 guaranteed, rarely 13 | Prediction: 13 guaranteed, rarely 14 |
| Level 5-7 | 12 guaranteed | Prediction: 13 guaranteed |
| Level 8 | Usually 12, rarely 11 | Prediction: 12 guaranteed, rarely 13 |
| Level 9 | Usually 11, rarely 12 | Prediction: Usually 12 |
| Level 10 | 11 | Prediction: 11, rarely 12 |
| Level 11 | 11 | 11 |
In deciding whether or not to take Fast Learner, remember that it’s not only about getting bonus perks (getting 14 means you get 2 extra perks, 13 means 1 extra, 12 means you break even), but also that you can get an extra health boost on the perk rolls (3 extra regen for 14, 2 for 13, 1 for 12) and you are typically getting perks a room earlier (which means you can use it for 1 more room than you otherwise would have)