ReckonBoxRoll any dice, and see the odds behind them
A dice roller simulates throwing physical dice, generating a fair random result for one die or a whole handful at once. Pick the number of dice, the number of sides, and an optional modifier, and this tool shows every die, the total, and the range you should expect.
That last part is where it goes past the usual roller. Plenty of sites will roll 3d6 and print a number. Almost none tell you that 3d6 runs 3 to 18 and averages 10.5, so a total of 14 reads as a good roll rather than a mysterious one. The shape of the roll is as useful as the roll itself.
Reading dice notation
Dice notation is a shorthand where NdS means N dice of S sides, and a trailing number is a fixed modifier added to the total. So 3d6+2 means roll three six-sided dice and add 2.
The letter d stands for die, the number before it is the quantity, and the number after it is the faces. A single twenty-sided die is 1d20, the backbone of many tabletop games. Damage from a longsword might be 1d8 plus a strength modifier, and a classic character stat is 3d6. This tool assembles that expression from the three fields and prints it above the result, so the notation and the roll always match.
The math of a roll
Three numbers describe any dice expression, and they are worth knowing before you trust a result. The minimum is N plus the modifier, when every die lands on 1. The maximum is N times S plus the modifier, when every die shows its top face. The average is N times S plus 1, over 2, plus the modifier.
A single six-sided die averages 3.5, halfway between 1 and 6. Three of them average 10.5, and 3d6+2 averages 12.5 while running 5 to 20. Rolling many dice also tightens the spread toward that average: one d6 is equally likely to be any face, but the total of several clusters around the middle, which is why 3d6 hits 10 or 11 far more often than 3 or 18. This tool prints the minimum, average, and maximum beside every roll so you can place the number in that context.
Fair, but not the atomic clock
This roller uses your browser's cryptographic random generator, a cryptographically secure pseudo-random source, which is more even than most physical dice. A real die has tiny weight imbalances from its pips and its molding, so a virtual roll is arguably fairer than the cube in your hand. For draws where money or fairness disputes are on the line, some tools reach for hardware or atmospheric-noise sources, which RANDOM.ORG uses because true physical noise is harder for anyone to predict or reproduce than any algorithm. For a board game, the browser generator is well past good enough.
Beyond a single throw
The roller handles the full polyhedral set, a four, six, eight, ten, twelve, twenty, and hundred-sided die, and up to 100 of them in one throw. Because it shows each die and not only the sum, you can apply per-die rules yourself, like keeping the highest or reroll a 1. It deliberately stops short of scripting whole rule systems, so it stays a quick, honest roller rather than a game engine.
Next time you roll a 16 on 3d6, the tool will remind you the average is 10.5, so you earned a genuinely good result and not a routine one.
Frequently asked questions
What does dice notation like 3d6+2 mean? Dice notation is a shorthand where the first number is how many dice, the letter d marks the die, the next number is how many sides, and a trailing number is a fixed modifier. So 3d6+2 means roll three six-sided dice and add 2 to the total. A single twenty-sided die is 1d20, and a longsword hit in many tabletop games is 1d8 plus a strength modifier. This tool builds that expression from the fields and shows it.
What is the average of a dice roll? The average of an N-dice, S-sided roll is N times (S + 1) divided by 2, plus any modifier. One six-sided die averages 3.5, so 3d6 averages 10.5, and 3d6+2 averages 12.5. The roll runs from a minimum of N plus the modifier, when every die shows 1, to a maximum of N times S plus the modifier. This tool prints that minimum, average, and maximum next to your result so you can see whether a roll was lucky.
Are online dice truly random? This roller uses your browser cryptographic random generator, which is a cryptographically secure pseudo-random source, and it is more than fair enough for games and more even than most physical dice, which are rarely perfectly balanced. For draws where the stakes are high, some tools use hardware or atmospheric-noise sources for true randomness, which RANDOM.ORG explains is harder for anyone to predict or reproduce than an algorithm.
What dice can I roll? You can roll the standard polyhedral set of a four, six, eight, ten, twelve, twenty, and hundred-sided die, and up to 100 of them at once. Pick the number of dice, choose the sides, and add a modifier if your game calls for one. The result shows every individual die so you can apply per-die rules yourself, along with the combined total.
Why show the minimum, average, and maximum? Because a total on its own does not tell you much. A 14 on 3d6 sounds fine until you see the roll runs 3 to 18 and averages 10.5, which makes 14 a good but not extraordinary result. Printing the range and average turns a bare number into context, and it is the piece most dice rollers leave out. It also helps when you are choosing between dice expressions for a game you are designing.