D10 Dice Roller

The die that doesn’t fit the pattern

The d4, d6, d8, d12 and d20 are all Platonic solids, shapes the ancient Greeks wrote about where every face is the same regular polygon. There are only five of them, and none has ten faces. So the d10 cheats a little. It’s a pentagonal trapezohedron: ten kite-shaped faces arranged around two pointed ends, five on top and five on the bottom, twisted so the faces interlock. Every face is identical, so it rolls fairly, but it looks noticeably different from the rest of the set.

It also gets used in two very different ways, which is why this page exists. Some games roll a d10 as a simple one-to-ten number. Others count how many d10s in a handful come up high. We’ll take them one at a time.

Job one: a single number from one to ten

In Dungeons & Dragons fifth edition, the d10 is a damage die for some of the most common attacks in the game:

Source	Roll
Fire Bolt cantrip	1d10 fire, rising to 4d10 at level 17
Eldritch Blast	1d10 force per beam
Heavy crossbow, glaive, halberd, pike	1d10 damage
Longsword, battleaxe or warhammer used two-handed (versatile)	1d10 damage
Fighter, paladin and ranger Hit Die	1d10 per level

The average is 5.5. Eldritch Blast is the classic multi-dice roll here, since a high-level warlock fires several beams and each one rolls separately for its attack, then its own d10 for damage.

Reading a physical d10

Most d10s are printed 0 to 9, with the 0 read as a 10. That trips up new players constantly. This roller shows 1 to 10, so there’s nothing to decode.

Job two: counting successes in a pool

The other big d10 tradition comes from the World of Darkness games, including Vampire: The Masquerade. Instead of adding dice together, you roll a pool of d10s, often three to eight of them, and count how many show a “success.” In the current fifth edition of Vampire, any die showing 6 or more counts as a success, which makes each die a coin flip.

The maths of pools surprises people. Here’s the chance of getting at least a given number of successes when each die succeeds half the time:

Dice in pool	At least 1 success	At least 2	At least 3
1	50%	0%	0%
2	75%	25%	0%
3	87.5%	50%	12.5%
4	93.8%	68.8%	31.3%
5	96.9%	81.3%	50%
6	98.4%	89.1%	65.6%

Adding a die to a pool of three barely moves the “at least one” column, but it more than doubles your shot at three successes. That’s why experienced players fight for every extra die.

Rolling a pool here

Set Dice to the size of your pool and roll. The roller shows each die individually, so count the ones at 6 or above yourself. The total isn’t useful for pools, so ignore it.

The single-die numbers

Probabilities for one d10

Roll	Chance of exactly this	Chance of this or higher
1	10%	100%
2	10%	90%
3	10%	80%
4	10%	70%
5	10%	60%
6	10%	50%
7	10%	40%
8	10%	30%
9	10%	20%
10	10%	10%

Each face has a 10% chance. The neat thing about a d10 is that every number is exactly ten percentage points, so “roll 7 or higher” is instantly 40%.

Percentile rolls with two d10s

Put two d10s together, one for the tens and one for the units, and you’ve got a d100, a number from 1 to 100. Call of Cthulhu runs its entire skill system on this, and older D&D editions used it for everything from treasure tables to thief skills. Most sets include a special d10 marked 00, 10, 20 and so on for the tens.

When both dice show zero, that’s 100, not 0. It’s the single most argued-about rule at new tables. The main dice roller has a d100 option that skips the argument, and the 1 to 100 number page explains how to turn a percentage chance into a roll.

d10 uses away from the table

• Ratings out of ten. Roll a “critic score” for a made-up film in a writing exercise.
• Ten-question quizzes. Roll for the order.
• Digit practice. Read 10 as 0 and you’ve got a random digit for place-value games, though the 0 to 9 page does that directly.

Need a bigger die? The d12 roller is next, and the d20 page covers advantage and critical hits.

Exploding tens and other house rules

Several d10 systems use “exploding” dice: when a die shows a 10, you count it and roll it again, adding the new result. Older World of Darkness games used a version of this, and some groups bolt it onto other systems for extra drama. The odds are easy to reason about. Any single die explodes one time in ten, a second explosion on the same die is one in a hundred, and a third is one in a thousand.

To play exploding dice here, roll your pool, count how many tens you got, and roll that many extra dice straight away. Keep going until no tens appear. It takes a few seconds longer than a single click, but you’ll see every die, so nobody can doubt the chain.

Critical successes in Vampire

In the fifth edition of Vampire: The Masquerade, each pair of tens in a pool counts as a critical, worth four successes instead of two. With a pool of five dice, you’ll roll at least two tens about 8% of the time. It’s rare enough to feel special and common enough that it’ll happen a few times in a long chronicle.

Ten-sided dice and the decimal system

There’s something pleasingly tidy about a die that matches the way we count. Any number you’d write in base ten can be built one d10 at a time, reading 10 as 0: roll once for each digit, left to right. Four rolls make a four-digit number from 0000 to 9999 with every value equally likely. It’s the same principle as percentile dice, just extended, and it’s a nice way to show students that big random numbers are only small random numbers lined up in a row.

Reading results at a glance

When you roll a big pool here, the dice appear in a row in the order they were rolled. To count successes quickly, scan once for anything 6 or higher and once more for tens. It’s faster than it sounds, and it’s how most Vampire players read a physical pool anyway.