Dice Simulator
Simulate any die from a d2 to a d100. Every roll shows the faces, the total, and the exact odds of landing that total or better.
Press Roll to throw the dice.
Press Space to roll again. Type notation like 2d6+3 or 4d6dl1 straight into the box.
Recent rolls
- No rolls yet.
How the randomness actually works
The numbers come from Math.random, the generator built into
your browser. It is pseudorandom: a formula seeded once when the page
loads, producing a sequence that has no pattern a person could spot or
exploit. Each roll takes one value from that sequence, multiplies it by
the number of sides, and rounds down.
That is worth saying plainly because plenty of sites imply something more exotic. There is no atmospheric noise here and no hardware entropy source. For a board game, a homework exercise, or a tabletop session, the difference does not exist. For anything where money changes hands, use a generator built for it.
Fairer than the die in your drawer
A cheap moulded die is measurably unfair. The pips are drilled out and filled with lighter paint, so the 6 face weighs slightly less than the 1 opposite it, and the die favours the 6. Corners round off with use. Casino dice are machined flat, filled flush, and retired after a few hours because even that is not enough.
A simulated die has no mass and no corners to wear. Every face has identical odds on every roll, from the first to the ten-thousandth.
Reading the odds line
After each roll the simulator tells you the chance of hitting that total or higher. Those figures are computed exactly, not estimated by running the roll a million times. On 2d6, seven is the most common total because six of the 36 combinations add up to it, while twelve has only one.
The dice probability page works through where those numbers come from. If you want to reproduce a specific result, the copy-link button on the main dice roller encodes the seed, so the same roll comes back on any device.
FAQ
Where do the random numbers come from?
From your browser's Math.random, which is a pseudorandom generator seeded by the browser at startup. It produces values with no pattern you could exploit at a game table, and every roll is worked out on your device rather than on a server.
Is Math.random good enough for a game?
Yes, for a game. It is not designed to be unpredictable to an attacker who can watch the output, so it is the wrong tool for anything involving money or cryptography. For deciding whether your rogue hits, it behaves like a fair die.
Why did I roll four 6s in a row?
Because that happens. Four 6s on a d6 comes up once in 1296 attempts, which sounds rare until you notice how many rolls a session contains. Runs are what real randomness looks like; evenly spaced results would be the suspicious outcome.
Can the simulator be biased toward certain numbers?
Not in any way you would notice. Each face is picked by scaling a uniform value across the number of sides, so every face has the same chance. Unlike a moulded plastic die, there is no hollow pip on one side making the opposite face heavier.