Dice Roller (Online Dice)

How to use the Dice Roller

1. Choose the number of dice, from 1 to 6. For games that use two dice, like Monopoly, Catan or backgammon, choose 2.
2. Choose the dice type. A standard six-sided die is a d6. You can also pick the 4-, 8-, 10-, 12- and 20-sided dice used in tabletop RPGs.
3. Press the Roll button or the spacebar. The dice shake, and then each result and the total appear.
4. The stats below show how many times you've rolled, your average total and how often each face has come up. If you change the number or type of dice, the stats start over.

Odds for the Total of Two Dice (2d6)

Two six-sided dice can land in 6 × 6 = 36 different ways. Here's how many of those ways give each total, and the chance of each total:

7 is the most common total because more combinations add up to 7 than to any other number: (1,6), (2,5), (3,4), (4,3), (5,2) and (6,1). On the other hand, 2 and 12 are the rarest totals because each one has only a single combination, (1,1) or (6,6). The average (expected value) of two dice is 7. That's why the robber moves on a 7 in Catan and why 6s and 8s are the best numbers to build on.

Is an Online Dice Roller Fair?

Real dice can favor some faces very slightly because of worn edges or an uneven center of mass. Tooljip's dice roller picks each face with your browser's cryptographic random number generator (crypto.getRandomValues). It also removes the bias that can creep in when random numbers are mapped onto a range, so every face has exactly the same chance of coming up.

That doesn't mean the faces will come up evenly over a few rolls. After 30 or so rolls, it's common for one face to show up a lot more than the others. Over hundreds or thousands of rolls, the share for each face gets closer to the theoretical value (about 16.7% on a d6). This is called the law of large numbers. You can watch it happen in the stats table.

What Are d4, d8, d10, d12 and d20 Dice Used For?

Polyhedral dice are mostly used in tabletop role-playing games (TTRPGs) such as Dungeons & Dragons and Pathfinder. For example, you roll a d20 to see if an attack hits, and a d4 to d12 for damage, depending on the weapon. In dice notation, "2d6" means two six-sided dice and "1d20" means one twenty-sided die.

If you need a random number in a custom range instead of a dice roll, try the random number generator. To pick between two options, use the coin flip.