Dice Roller
100% private — runs on your device, never uploaded. Works offline once loaded.
Roll any dice using tabletop notation like 2d6+3 or d20 — choose the number of dice, sides and modifier, or just type the expression. Each roll uses your browser's cryptographic randomness for genuinely fair results.
Reading dice notation
Tabletop games describe dice with a compact shorthand: NdS means roll N dice each with S sides, and an optional +M or -M adds or subtracts a fixed modifier from the total. So 2d6+3 means roll two six-sided dice and add three, giving a result between 5 and 15. Leaving the count off, as in d20, implies a single die. This roller accepts that notation directly in the text box, and also lets you dial the same values in with the count, sides and modifier controls — whichever you edit, the other updates to match.
The most common dice in role-playing games are the d4, d6, d8, d10, d12, d20 and d100 (usually rolled as two d10s), all available in the sides menu. The modifier is where character bonuses live: a +3 attack bonus or a -1 penalty simply shifts the total without changing the dice.
Why cryptographic randomness matters
Most casual random tools reach for Math.random(), which is fast but produces predictable, low-quality pseudo-randomness not intended for anything where fairness matters. This roller instead draws from crypto.getRandomValues, the same cryptographically secure generator browsers use for security-sensitive work, so the sequence cannot be easily predicted and no face is quietly favoured over another.
There is a subtle trap even with a good random source: naively taking a random 32-bit number modulo the die size introduces modulo bias, making some faces very slightly more likely than others. The roller avoids this by rejecting and re-drawing any value that falls in the uneven tail of the range, so a d6, a d20 and a d100 are all perfectly uniform.
Where a dice roller is handy
Beyond running a Dungeons & Dragons or Pathfinder session without physical dice, an online roller is useful whenever you need a fair random outcome or want to keep play moving when dice have rolled off the table.
- Tabletop RPGs — attack rolls, saving throws, damage and ability scores.
- Board and card games that call for dice but the set has gone missing.
- Teaching probability — roll 2d6 many times to see the bell-curve of totals.
- Making fair decisions or picking a random number in a fixed range.
- Play-by-post and online games where everyone needs the same trustworthy roller.
Understanding the odds
A single die is uniform: every face is equally likely, so a d20 gives each number from 1 to 20 a flat 5% chance. Adding dice together changes the shape dramatically — rolling 2d6 makes a total of 7 six times more likely than a 2 or a 12, because there are more combinations that sum to 7. This is why many games use multiple dice for effects meant to cluster around an average, and single dice for swingy, high-variance rolls. The roller shows the individual dice alongside the total so you can see exactly how a result was built up, with the highest and lowest possible faces highlighted.
Frequently asked questions
Can I roll several different dice at once?
Each roll uses one notation expression, so you roll a batch of matching dice like 4d6 together. For mixed pools, roll each type in turn — the individual results and totals are shown each time.
What is the maximum I can roll?
You can roll up to 100 dice at a time, with up to 1000 sides each, which covers every standard RPG die and then some.
How does the modifier work?
The modifier is added to the sum of the dice, not to each die. So 2d6+3 rolls two d6, adds them, then adds 3 once to the total.
Does typing notation override the dropdowns?
Yes. If the notation box holds a valid expression like 3d8+2 it takes priority; clear it to roll using the count, sides and modifier menus instead.
Why do my 2d6 totals cluster around 7?
Because more dice combinations add up to 7 than to any other total. Summing multiple dice produces a bell-shaped distribution centred on the average, unlike a single die where every face is equally likely.
Is anything about my rolls stored?
No. Rolls are generated in your browser and nothing is logged, saved or transmitted — refreshing the page clears everything.
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