How the rolls work
Every press of the roll button asks your browser's cryptographic random number generator (the same machinery used to create encryption keys) for fresh, unpredictable values, then maps them onto the faces of your chosen die using rejection sampling. That technique avoids the small bias naive methods introduce, so a d20 really does give each of its 20 faces an exactly equal 5% chance, and a d6 gives each face 1 in 6.
The roll happens entirely on your device. Nothing is sent to a server, so nobody (including us) can see or nudge the outcome, and there is no roll history stored anywhere.
Averages and odds worth knowing
A d6 averages 3.5 per roll, a d10 averages 5.5 and a d20 averages 10.5. Multiply by the number of dice for the expected total: five d6 average 17.5. Totals also bunch towards the middle when you roll more than one die, because there are far more ways to make a middling sum than an extreme one.
Which die does what
- d6: the familiar cube from Monopoly, Yahtzee, backgammon and almost every family board game.
- d20: the signature die of Dungeons and Dragons, rolled for attacks, saving throws and skill checks.
- d4, d8, d10 and d12: damage and effect dice in tabletop role-playing games, each tied to different weapons and spells.
- Percentile (d100): roll a d10 twice, read the first as tens and the second as units, and treat a double zero as 100.
If the die you need is missing a friend's kitchen table, this page stands in for all of them at once: set the type, set the quantity and roll. The highest and lowest rows are handy for games that use advantage or disadvantage, where you roll twice and keep one result.
Digital versus physical dice
A well-made physical die is close to fair, but cheap dice rarely are. Rounded corners, uneven paint fills and tiny air bubbles all shift the balance point, and studies of mass-produced dice have found some faces coming up measurably more often than others. That is exactly why casinos insist on precision-machined dice with sharp edges and flush paint, and replace them frequently.
A cryptographic roll has none of those problems. There is no weight to be off-centre and no wear to accumulate, so every roll is as fair as the last. The one thing it shares with real dice is streakiness: runs of high or low numbers are normal in genuinely random sequences, and a run of three 20s says nothing at all about the next roll.
Frequently asked questions
Are the rolls fair?
Yes. Each roll uses your browser's cryptographic random number generator (crypto.getRandomValues) with rejection sampling, so every face of the die has an exactly equal chance. That is far stronger than the basic Math.random most tools rely on.
What do d4, d6 and d20 mean?
The number after the d is the number of sides. A d6 is the familiar cube from board games, while d4, d8, d10, d12 and d20 are the dice used in tabletop role-playing games such as Dungeons and Dragons.
Can I roll several dice at once?
Yes, up to 20 of the same type in one click. The tool lists every individual result and shows the total, the highest roll and the lowest roll underneath.
Is a digital roll as good as a real die?
Often it is fairer. Cheap physical dice have rounded corners, uneven paint and air bubbles that skew results slightly, which is why casinos use precision-machined dice. A cryptographic roll has no physical imperfections at all.
Why is there no d100?
You can make one easily: roll a d10 twice, use the first roll for tens and the second for units, and read a double zero as 100. Alternatively, use our random number generator set to 1 to 100.