10 Sided Dice Roller (D10)
Roll up to 15 ten-sided (D10) dice at once and get the total, expected value, probability of each possible sum, and a full distribution chart. Add a flat modifier for RPG skill checks, damage rolls, or any game mechanic that needs it. Every roll is randomly generated in your browser. Change the number of dice or the modifier and the statistics update instantly alongside the new roll result.
What is a D10 die?
A D10 is a ten-sided polyhedral die shaped as a pentagonal trapezohedron. It is one of the standard dice used in tabletop role-playing games such as Dungeons and Dragons, Vampire: The Masquerade, and countless wargames. The faces are numbered 1 to 10 on a standard die, or 0 to 9 on the tens-place die used for percentile (D100) rolls. Each face has an equal 10% probability of landing face-up on any given roll, making the D10 a fair uniform discrete distribution over its ten faces.
How this calculator works
Enter the number of D10s you want to roll (up to 15) and an optional flat modifier. A new random roll is generated every time you change the seed input. The calculator displays the roll total (sum of all dice plus the modifier), the raw dice sum before the modifier, the expected value for this configuration, the minimum and maximum possible totals, and the probability of rolling at least the current sum or the exact sum. The probability chart shows the full probability mass function and cumulative distribution for the sum of your chosen number of dice, so you can see at a glance how likely any particular total is.
Rolling two D10s as a percentile die (D100)
Two D10s can simulate a 100-sided die. One die represents the tens digit (00, 10, 20, through 90) and the other represents the units digit (1 through 0). Read them together to get a number from 01 to 100 (or 00 to 99, depending on convention). A roll of 70 on the tens die and 3 on the units die gives 73. This is called a percentile roll and is used in games like Call of Cthulhu and Warhammer Fantasy Roleplay for skill checks where success is determined by rolling under a percentage threshold. Switch the die faces selector to "0 to 9" to simulate the tens-place die on its own.
Expected value and probability for multiple D10s
The expected value of a single D10 (faces 1-10) is (1+2+...+10)/10 = 5.5. For N dice, the expected sum is N x 5.5, growing linearly. As you add more dice, the distribution of possible sums becomes more bell-shaped (by the Central Limit Theorem) and concentrates around the mean: the chance of an extreme result drops sharply. Two dice give possible sums from 2 to 20 with a peak at 11; five dice give sums from 5 to 50 with a peak near 27-28. The probability chart shows this distribution for any count you choose.
D10 single-die probability table
| Face value | Probability | Cumulative probability |
|---|---|---|
| 1 | 10.00% | 10% |
| 2 | 10.00% | 20% |
| 3 | 10.00% | 30% |
| 4 | 10.00% | 40% |
| 5 | 10.00% | 50% |
| 6 | 10.00% | 60% |
| 7 | 10.00% | 70% |
| 8 | 10.00% | 80% |
| 9 | 10.00% | 90% |
| 10 | 10.00% | 100% |
Probability of rolling each face on a single standard D10 (faces 1-10). Every face has equal probability of 10%.
Frequently asked questions
What is the average roll on a D10?
For a standard D10 numbered 1-10, the average (expected value) of a single roll is 5.5. This is because each face is equally likely, so the mean is (1+2+3+4+5+6+7+8+9+10) / 10 = 55 / 10 = 5.5. For the 0-9 variant used in percentile rolls, the average is 4.5.
What is a percentile roll and how do two D10s make a D100?
A percentile roll uses two D10s together. One die (the tens die, often a different color or labeled 00-90) gives the tens digit, and the other gives the units digit. Combining them produces a number from 01 to 100 (or 00 to 99). For example, tens die = 40, units die = 7 gives 47. A result of 00 on the tens die and 0 on the units die is usually read as 100. This gives a uniform distribution across 100 outcomes, useful for percentage-based skill checks.
How is a D10 different from a D12 or D8?
The D10 has ten faces (pentagonal trapezohedron), giving outcomes 1-10. The D8 has eight faces (octahedron) giving 1-8, and the D12 has twelve faces (dodecahedron) giving 1-12. The D10 is unique because it is the only standard polyhedral die whose face count is a power of ten, which is why it is used for percentile rolls. The D8 and D12 do not share this property.
Can I add a modifier to my D10 roll?
Yes. Enter a positive or negative modifier in the Modifier field. The modifier is added directly to the sum of all dice rolled. This mirrors how RPG systems handle ability score bonuses and penalties: for example, rolling 2D10 with a +3 modifier and getting a dice sum of 14 gives a final total of 17. The expected value, minimum, and maximum all shift by the same modifier amount.
What is the probability of rolling a specific number on a D10?
For a single D10 the probability of any specific face is exactly 1/10 = 10%. For the sum of multiple dice the probability depends on how many ways that sum can be achieved. The probability of rolling a sum of 11 on 2D10, for instance, is 10/100 = 10% because there are 10 combinations that sum to 11 out of 100 equally likely outcomes.
Is this dice roller truly random?
The calculator uses a deterministic pseudo-random number generator seeded by the value you enter in the seed field. This means the same inputs always produce the same roll (making the calculator reproducible and testable), but changing the seed gives a statistically uniform distribution across many seeds. For gaming use where true unpredictability matters, physical dice or a cryptographically secure random source is more appropriate. For statistics and probability education this tool is ideal.