## Dice Odds for Every Type (d4, d6, d8, d10, d12, d20)

Posted by Jeff McArthur on Sep 1st 2014

I myself prefer to have some mystery in my gaming, so I don’t try to calculate odds while playing. What are the odds of my sword “The Goblin Smasher of Good” killing the evil plague rat troll-witch before it destroys the innocent village? Who cares? Go forth and save the day! I find that those people who stall and start calculating the odds are missing the point of story-based gaming; and are, in my view, sort of buzz-kills.

However, when developing games, sometimes the odds are necessary to know what the chances will be that the players will come out victorious. You don’t want the game to be too easy or too hard. So you want to have a quick calculation of odds. There are the basics, such as to get any single number on each die type, and for those the odds are approximately:

D4 = 25%

D6 = 17%

D8 = 13%

D10 = 10%

D12 = 8%

D20 = 5%

For slightly more complicated odds, these are the odds of getting a number equal to or greater than a target number on a single die:

 Die Mean Value Chance of this number or better 1 2 3 4 5 6 7 8 9 10 11 12 d4 2.5 100% 75% 50% 25% d6 3.5 100% 83% 66% 50% 33% 17% d8 4.5 100% 88% 75% 63% 50% 38% 25% 13% d10 5.5 100% 90% 80% 70% 60% 50% 40% 30% 20% 10% d12 6.5 100% 92% 83% 75% 67% 58% 50% 42% 33% 25% 17% 8% d20 10.5 100% 95% 90% 85% 80% 75% 70% 65% 60% 55% 50% 45%

But if you really have complicated odds to calculate, here’s where you go: