Topic: Probability breakdown for open-ended tables...?

[Mordenkainen]

Has anyone worked up a spreadsheet or other tool to show the probability of different results when rolling open-ended? For example, what are the odds of rolling 300+?

[Marc R]

5% chance of rolling open ended up once.

You'd need to roll open ended up a minimum of three times

%0.0125 chance of doing that. (1:8,000 chance)

The odds get somewhat ambiguous there. . .if you rolled 100 three times, you're done. . .if you rolled 96 three times now you need to roll over a 12.

So a 300 is somewhere around %0.0125 and %0.0110. . .say between 1:8,000 and 1:9,000.

So "rolling at least a 300" is %0.0125. . .

If you draw it as a curve, the odds plummet off every increment of 95-100, then curve to the next, then plummet, then curve, then plummet, etc.

[VladD]

As I loathe to do math, I recall seeing the open-ended break down somewhere in the Guild Companion archives.

Sorry but I'm not checking it again to give the link.