D8 dice roller

An 8-sided die in one click

On this page, the dice roller opens set to an 8-sided die, the d8. Click "Roll the dice", click the die or press the space bar: a number from 1 to 8 appears after half a second. The roll comes from your browser's cryptographic random number generator, every side has the same chance, and nothing is sent.

You can roll up to 20 dice at once ("Number of dice") and read the total, change the "Number of sides" or use the "Quick picks" buttons. Your last 12 results stay visible under "Latest rolls".

What is a d8 used for?

A real d8 is an octahedron: eight triangular faces, like two pyramids glued base to base. It rolls well and you read the face on top.

• Tabletop role-playing games: damage for mid-sized weapons such as a longsword or a crossbow, and hit points gained by some characters.
• Picking a compass direction: 1 = north, 2 = northeast, 3 = east, 4 = southeast, 5 = south, 6 = southwest, 7 = west, 8 = northwest. Handy for moving a wandering monster or a storm across a map.
• Picking a day of the week: 1 = Monday through 7 = Sunday, and reroll on an 8. Each day then gets exactly a 1 in 7 chance.

The odds with a d8

Each side has a 1 in 8 chance, or 12.5%. The average is (1 + 2 + … + 8) ÷ 8 = 36 ÷ 8 = 4.5. Rolling 5 or higher happens half the time.

For the day of the week, you only reroll on an 8, so 12.5% of the time: on average it takes 8 ÷ 7 ≈ 1.14 rolls to get a day.

Frequently asked questions

Is a d8 the same as 2d4?

No. 2d4 ranges from 2 to 8 with an average of 5, and a total of 5 comes up 25% of the time. A d8 ranges from 1 to 8 and every value has 12.5%. Use the notation your rules ask for.

How do I roll critical damage, 2d8?

Put 2 in "Number of dice" and roll: both results and their total appear. Flat bonuses still have to be added in your head.