Roll any dice, with the exact odds of every total.
Who this is for: Board games, tabletop RPGs and probability lessons.
Rolled in your browser with the Web Crypto API.
Probability of each total, 2d6
Exact, from the distribution of the sum of 2 fair 6-sided dice.
Total
Exactly
This or higher
2
2.78%
100.00%
3
5.56%
97.22%
4
8.33%
91.67%
5
11.11%
83.33%
6
13.89%
72.22%
7
16.67%
58.33%
8
13.89%
41.67%
9
11.11%
27.78%
10
8.33%
16.67%
11
5.56%
8.33%
12
2.78%
2.78%
Calculated in your browser — the numbers you enter are never sent to our servers.
Roll any number of dice — d4, d6, d8, d10, d12, d20, d100 or a custom die — with a modifier, advantage or disadvantage, and see the exact probability of every possible total. Rolls are made in your browser with the Web Crypto API, so every face is equally likely.
Best for: Board games, Tabletop RPGs, Classroom probability, Settling who goes first
Updated September 2026 · Estimates only, not financial advice.
Why 7 comes up once in every six rolls of two dice
Two six-sided dice have 6 × 6 = 36 equally likely outcomes, but the totals are not equally likely. Only one pair makes 2 (1+1) and only one makes 12 (6+6), while six pairs make 7. So 7 has a probability of 6/36, or 16.67%, and 2 or 12 only 1/36 each, about 2.78%.
The probability table under the roller works this out exactly for any dice, adding one die at a time. With three dice the totals 10 and 11 are the most likely, at 27/216 (12.5%) each, and a total of 10 or more comes up 135 times in 216, or 62.5% of the time.
How every face stays equally likely — and the bias a naive roller has
Computers produce random bits, and a d6 needs a number from 1 to 6. The obvious method — take a random 32-bit number and use the remainder after dividing by 6 — is very slightly biased, because 2^32 is not a multiple of 6, so the lowest remainders turn up a hair more often.
This roller uses rejection sampling instead: it throws away the handful of raw values in the uneven tail and draws again, so all six faces have exactly the same chance. The raw bits come from crypto.getRandomValues, the browser’s cryptographically secure generator, not the predictable Math.random that many simple rollers use. Nothing is sent to a server.
Advantage raises the chance of 15 or more on a d20 from 30% to 51%
Some tabletop games roll two twenty-sided dice and keep the higher (advantage) or the lower (disadvantage). On a single d20, 15 or more comes up 6 times in 20, or 30%. With advantage you fail only if both dice are 14 or lower: 1 − (14/20)² = 51%. With disadvantage you need both to be 15 or more: (6/20)² = 9%.
Choose Advantage or Disadvantage at the top of the roller and it rolls the whole pool twice, keeps the right total and shows the one it dropped.
Reading 3d6+2: three six-sided dice, plus two
Dice notation writes the number of dice, the letter d, and the number of sides: 1d20 is one twenty-sided die, 4d6 is four six-sided dice, and d100 (or d%) is a hundred-sided die, usually rolled as two ten-sided dice. A +2 or −1 afterwards is a modifier added to the total.
The roller shows the notation for whatever you set, and the average total is n × (s + 1) ÷ 2 plus the modifier: 3d6+2 averages 3 × 3.5 + 2 = 12.5.
The more dice you roll, the more the total bunches around the average
One die gives every face the same chance — a flat distribution. Add dice and the totals pile up in the middle, because there are more ways to make middle totals. The spread grows only with the square root of the number of dice: the standard deviation of one d6 is 1.708, of 2d6 is 2.415, and of 10d6 is 5.401, while the range grows tenfold.
That is why rolling 3d6 for a character trait gives far fewer extreme values than rolling 1d16 and adding 2, even though both run from 3 to 18: a total of 18 is 1 in 216 on 3d6 but 1 in 16 on 1d16 + 2.
Worked example
Two six-sided dice.
Worked example
Possible totals = 2 to 12
Most likely total = 7 (6 in 36, 16.67%)
Average = 7
Standard deviation = 2.415
Limitations
Not for regulated gambling or official draws, which need certified equipment.
The probability table assumes fair dice; a physical die can be biased.
Frequently Asked Questions
What is the most common roll with two dice?
7. Six of the 36 equally likely pairs add to 7 (1+6, 2+5, 3+4, 4+3, 5+2, 6+1), so it comes up one time in six.
Is an online dice roller fair?
This one draws each die from the browser’s cryptographic random number generator and discards the few raw values that would make low faces more likely, so every face has exactly the same chance.
Sources & References
Figures on this page are checked against primary, authoritative sources. Links open in a new tab.
ProbabilityTwo events, repeated trials and Bayes, with the three usual errors handled — the dropped overlap in P(A or B), n×p instead of the complement, and the base rate that makes a 99% test 17% right.
Random Number GeneratorPick random numbers in any range, with or without repeats, sorted or as drawn, in whole numbers or decimals.
Expected ValueReports the spread, the chance of any gain and the single most likely outcome beside the average — because on a roulette number bet the expected value is −2.70% and the modal result is losing, 36 times in 37.
Binomial DistributionExact binomial probabilities at any n — including thousands, where a factorial overflows — with the normal approximation beside them and its error measured, which is 0.6% at the centre and 261% in the tail.
Password GeneratorStrong random passwords made on your device, with the entropy in bits and how long brute force would take.
Monty HallGeneralises the puzzle so the famous 100-door explanation stops hiding its own assumption — open one door instead of 98 and switching is worth 1.0102% against 1%, still right and barely.
Bicycle Tire PressureEstimate front and rear bicycle tire pressure from your weight, tire width, tire type, and terrain, using a published formula.
ConcreteCalculate cubic yards of concrete needed for a slab, footing, or column, and how many 40, 60, or 80 lb pre-mix bags to buy.