D&D General 1 in 1000 chance


log in or register to remove this ad

Dioltach

Legend
I had a streak a few years back when four or five sessions in a row I did not once roll higher than a 12. No matter which d20 I used (and I even made sure it wasn't a d12), it was just, "Yup, I missed again."
 

Mad_Jack

Hero
I had a streak a few years back when four or five sessions in a row I did not once roll higher than a 12. No matter which d20 I used (and I even made sure it wasn't a d12), it was just, "Yup, I missed again."

Slight thread derailment here, but there was one time several years ago that me and the rest of our party replaced this one knucklehead's D20's with duplicates that were numbered 1-10 twice, and he didn't even notice - after two sessions, we had to tell him we'd spiked his dice before he ragequit, lol.
 

el-remmen

Moderator Emeritus
Slight thread derailment here, but there was one time several years ago that me and the rest of our party replaced this one knucklehead's D20's with duplicates that were numbered 1-10 twice, and he didn't even notice - after two sessions, we had to tell him we'd spiked his dice before he ragequit, lol.
Oh My God Omg GIF by CBC
 

MarkB

Legend
Slight thread derailment here, but there was one time several years ago that me and the rest of our party replaced this one knucklehead's D20's with duplicates that were numbered 1-10 twice, and he didn't even notice - after two sessions, we had to tell him we'd spiked his dice before he ragequit, lol.
We had a similar occurrence with someone whose dice luck was absolutely terrible - he forgot his dice one session and borrowed some from another player. His dice luck that evening was so consistent with every other game that we didn't realise he'd accidentally picked out a 20-sided d10 until he rolled a zero.

And even then it was like, "well, if anyone could make a d20 roll a 0, it's him."
 


DND_Reborn

The High Aldwin
Every result is a 1 in a 1000 chance.
Not quite, since order isn't important. If it was, then there would be 1000 permutations and you would be correct. But rolling 4, 5, 6 for 15 damage is the same as rolling 6, 5, 4 or 5, 4, 6 or 4, 6, 5, etc.

Since order isn't important, there are 220 possible combinations, with some totals more common than others. For instance, a total of 15 can be achieved by any of the examples above, but also by rolling 10, 2, 3 or 8, 6, 1 or 4, 4, 7, and so on.

However, rolling 10, 10, 10 for a total of 30 is 1 in 1000, while other totals certainly are not, being much higher; such as a total of 16 or 17 with 75 in 1000 each.
 

Rabulias

the Incomparably Shrewd and Clever
Not quite, since order isn't important. If it was, then there would be 1000 permutations and you would be correct. But rolling 4, 5, 6 for 15 damage is the same as rolling 6, 5, 4 or 5, 4, 6 or 4, 6, 5, etc.
While order does not matter for the final dice total, each combination of dice is 1 of 1000 combinations. 4, 5, 6 and 6, 5, 4 both equal 15, but each is a unique roll in that sense.
 


el-remmen

Moderator Emeritus
Obviously, which is why I said "Not quite." ;)

Since the TOTAL is what is important, however, order doesn't matter... 🤷‍♂️
Thank you for explaining this so I didn't have to point it out to folks who think they are really clever (but apparently not clever enough to actually read the whole thread and see how many times others have made the same comment). The odds of such pedantry on ENWorld are much better than 1 in a 1000 apparently.
 

So what are the odds of rolling three "1"s on d20 in 10 rounds of combat?
The odds of rolling exactly three 1's is:

C(10,3) (1/20)^3 (19/20)^7 = about 1.05%, or about 1 chance in 95.5.

The chance of rolling 3 or more 1's is about 1.15%, or about 1 in 86.9.

Now for a couple stories of my own! I was playing a solo superhero game and the GM says, "Make a Notice check." I roll a 1.

He says, "What the heck. Go ahead and roll again." I roll a 1.

He must have kinda wanted me to notice whatever it was, because he said, "Third time's the charm?" I roll a 1.

1 chance in 8000!

On the other hand, years ago I was playing TORG, which has d20 rolls explode on 10s and 20s. We come across an enemy camp, and my cyberpriest decides to attempt a minor miracle to make their lives harder before we attack. (Miracles in TORG are usually very subtle and unpredictable.)

I roll a 20. Then a 10. Then a 20. Then a 17. (If I'm not mistaken, there's odds of about 1 in 4211 of doing that well or better.)

The GM just glares at me and says, "Fine! A pillar of fire descends from the sky and burns up the entire camp! Satisfied?!" :)
 
Last edited:


Never roll dice with the clergy - that woman could roll a nat 20 on a D6... :p
Not a D&D story, but apropos of this, I was in a gaming circle that played a lot of Here I Stand (the card-driven Reformation Era game) for a spell several years back.

Anyway, my brother, the Anglican priest, would always want to play the combined Protestants/English side. (We usually had four players at the time.)

We had to institute a table rule that he wasn't allowed to quote from Tyndall's English Bible or put on Protestant hymns before rolling dice. Although no matter what he tended to roll uncannily well playing that side in that game.
 

coyote6

Adventurer
Playing GURPS years ago, I rolled all 1s on 5d6 (1 in 7776) for damage enough times that it became a "Bob did it again" thing. Of course, that was the damage of my character's full auto primary weapon, so I rolled 5d6 a lot. Still, all ones happened more than all sixes with that weapon.

OTOH, I tossed some explosives (maybe a grenade, I don't recall) doing 8d6 damage, and did 48 damage. All sixes - that's 1 in 1,679,616.
 

I roll a 20. Then a 10. Then a 20. Then a 17. (If I'm not mistaken, there's odds of about 1 in 4211 of doing that well or better.)
I got the chance to sit down and thoroughly work this out today - it actually comes out to 1 chance in about 5130. (124747 chances in 6.4e8, to be precise.)
 
Last edited:

Epic Threats

An Advertisement

Advertisement4

Top