Sometimes a game tells you to use a "percentile dice" or a d100. That can be confusing if you're not used to it, so here's how it's done.

Novelty die notwithstanding, there's no such thing as a d100. Instead, you use any one of four methods:

- Two ten-sided dice (d10) rolled in succession
- Two different colours of ten-sided dice (d10) rolled together
- A percentile die and a d10
- Any other way you know to get a random number between 0 and 99

You've gone out and bought exactly one dice set, and so you've got exactly one ten-sided die.

- Roll your d10 once. This is the
*tens*place. - Roll your d10 again. This is the
*ones*place. - Picture the two numbers you just rolled, side by side, to form a single digit.

For example, suppose you rolled an 8 and then a 2. You've rolled 82.

If you rolled a 1 and then a 9, then you've rolled 19.

If you rolled a 0 and a 1, then you've rolled a 1.

Here's the weird one: When you roll a 0 and a 0, you have rolled a 100.

If you've got two d10s, each a different colour, then you can use one as the *tens* die and the other as the *ones* die.
Declare which is which *before* you roll.
Personally, I have a green die that serves as my *tens* die, and a black die for *ones*.

- Roll both dice.
- Assemble a number from your roll result, based on which colour represents
*tens*and*ones*.

For example, suppose you roll a 7 and 5. You've rolled 75.

If you roll a 0 and 2, then you've rolled 2.

If you roll a 1 and 0, then you've rolled 10.

Here's the weird one: When you roll a 0 and a 0, you have rolled a 100.

You can buy a special "percentile" die from your friendly local game store.
Instead of single digits, it's got double digits on it.
It's a lot like using a different colour die as your *tens* die, except instead of a different colour it's just got more numbers on it.

- Roll both dice.
- Combine the percentile die with the d10 result.

For example, suppose you roll a 30 and a 3. You've rolled 33.

If you roll a 00 and then a 3, then you've rolled 3.

If you roll a 10 and a 0, then you've rolled 10.
That's tricky, because it looks like 100, but it's not.
It's one *ten* with zero *one* added on.

So how do you get 100? When you roll a 00 and a 0, you have rolled a 100.

If it helps, consider that the only time it's possible to get 100% of anything on percentile dice is when all digits are "0". When you roll three 0s, you have the only 100% possible, at least visually, on those dice.

Whether a roll of the highest value (000) is good, or whether you actually want a low roll (001) depends entirely on the game you're playing.
Games like **Call of Cthulhu** and **Stalking the Night Fantastic** reward low rolls (because you're aiming for a number within your range of skill), while other games reward high results because they represent a high likelihood of something occuring.

Regardless of the implications, though, you now know how to roll a d100.