d100 odds
- •Average roll: 50.5 (add the lowest and highest face and halve it: (1 + 100) / 2)
- •Each face: 1 in 100, or 1%
- •Chance of rolling 100: 1% per roll, 1.99% to see at least one in two rolls
| Number | Chance of this or lower | Chance of this or higher |
|---|---|---|
| 1 | 1% | 100% |
| 10 | 10% | 91% |
| 25 | 25% | 76% |
| 50 | 50% | 51% |
| 75 | 75% | 26% |
| 90 | 90% | 11% |
| 100 | 100% | 1% |
How to roll a d100 with two d10s
Percentile dice are two d10s. One is marked 00, 10, 20 … 90 for the tens, the other 0–9 for the ones. Roll both and add them: 40 and 7 is 47, 00 and 5 is 5, and 00 with 0 is 100. With two plain d10s, say which colour is the tens before you roll.
Don't add two d10s as numbers. 2d10 gives 2–20 with most results near 11. A real d100 gives every number from 1 to 100 the same 1% chance.
Percentile odds are easy to read: rolling N or lower is exactly N%. A table entry that covers 01–15 comes up 15% of the time.
What uses a d100 in D&D 5e
- •Reincarnate: the DM rolls a d100 to pick the creature's new body.
- •Wand of Wonder: each use rolls a d100 on its table of effects.
- •Robe of Useful Items: extra patches can be rolled on a d100 table.
- •Wild Magic Surge: the sorcerer surge table is a d100 roll. Roll it with the wild magic surge table.
- •Treasure and random tables: loot and encounter tables are often d100, like the ones behind the treasure generator.