Formula for high CR experience

[AthasianWarlock]

Hello all,

We just did something crazy in our game tonight. We managed to take out a CR 17 with a group of 4 level 9 and 1 level 8 character. When I put those numbers into the experience calculator it comes out with nothing. Can anyone help give me the formula?

Thanks

[retaliation08]

Weird it gave response for CR 15 and CR 16 (except the level 8).

[Fizban]

The table doesn't support awards for encounters 8 or more Challenge Ratings higher than the character's level. If the party is taking on challenges that far above their level, something strange is going on, and the DM needs to think carefully about the awards rather than just taking them off a table. See Assigning Ad Hoc Xp Awards, page 39.
So either you're the DM, and you need to think about what is going on in your game, or you're a player and you need to ask the DM.

[Elysiume]

RAW, the DM chooses. You're not expected to be able to do a fight that's 8 or more CR higher than your level, and it's assumed that something weird happened such that blindly handing out XP would be odd:

The [experience granted for CR'd encounters] table doesn't support awards for encounters eight or more Challenge Ratings higher than the character's level. If the party is taking on challenges that far above their level, something strange is going on, and the DM needs to think carefully about the awards rather than just taking them off a table. See Assigning Ad Hoc Xp Awards, page 39.

e: beaten

[AthasianWarlock]

DM basically told us not to try to kill it and told us it would kill us. We prepared specific items tailored to beat it (slaying arrows) and I got lucky and had a specter from call undead in the right spot at the right time give it 2 negative levels which made it exactly fail the slaying arrows DC and die.

[Elysiume]

It's still up to your DM. Mechanically, getting lucky with a SoD/SoS/whatever effect doesn't mean that characters should necessarily jump up an entire level at once. Flavor-wise, getting lucky with a SoD/SoS/whatever effect doesn't mean that characters necessarily learned that much, which is what XP theoretically maps to. The adhoc XP table basically says "if it was half as hard as it should have been, award half XP," so it boils down to your DM's judgment call on how much XP you should get.