Dice Roller With Modifier (d4, d6, d8, d10, d12, d20, d100)

Pick a die, choose how many to roll and add a bonus or penalty. You get every individual die plus the total, average, highest and lowest.

Runs in your browserFree, no sign-upLast reviewed October 8, 2026

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Quick answers

How do I roll 1d20+5?: Set Dice type to d20, How many dice to 1 and Modifier to 5, then press Roll. If the die shows 14, Total reads 19 and the breakdown beside it shows 14 + 5. The result range is 6 to 25 and the average is 15.5.
What does 2d6 mean?: Roll two six-sided dice and add them. The number before the d is how many dice, and the number after is the sides on each. So 3d8+2 means three eight-sided dice added together, plus 2.
What is the average roll of a d20?: 10.5. The average of any fair die is its number of sides plus one, divided by two: 2.5 for a d4, 3.5 for a d6, 4.5 for a d8, 5.5 for a d10, 6.5 for a d12 and 50.5 for a d100.
How do I roll with advantage or disadvantage?: Roll two d20s by setting How many dice to 2. For advantage use the Highest figure; for disadvantage use Lowest. Add your modifier yourself afterwards, because the Modifier field is applied to the sum of both dice.
What is the most common roll on two six-sided dice?: 7. Six of the 36 possible combinations add up to 7, a chance of 16.67%. The rarest totals are 2 and 12, each with one combination and a 2.78% chance.
Does the modifier apply to each die or to the total?: To the total, once. Rolling three d6 with a modifier of 2 gives the three dice added together plus 2, not plus 6. The Dice sum figure shows the result before the modifier.

What Dice Roller does

Choose a die from d4 to d100, set how many to roll (1 to 20) and enter a modifier such as +5 or -1. Press Roll and the tool lists each die separately, then shows five figures: Total (dice plus modifier), Dice sum, Average roll, Highest and Lowest. That covers the common tabletop rolls in one press. 1d20+5 is one d20 with a modifier of 5. Advantage is two d20s, reading Highest. A damage roll like 8d6 is eight d6s, reading Total. Each roll uses one die type, so a mixed roll such as 1d8 + 1d6 takes two presses. Every face has an equal chance on every die.

Dice types from d4 to d100: range, average and odds

The seven dice this roller offers, with the shape of the physical die each one stands in for.

Die	Results	Average roll	Chance of any one face	Physical shape
d4	1 to 4	2.5	25%	Tetrahedron (four triangular faces)
d6	1 to 6	3.5	16.67%	Cube
d8	1 to 8	4.5	12.5%	Octahedron
d10	1 to 10	5.5	10%	Pentagonal trapezohedron
d12	1 to 12	6.5	8.33%	Dodecahedron
d20	1 to 20	10.5	5%	Icosahedron
d100	1 to 100	50.5	1%	Usually two d10s read as tens and units

This d10 gives 1 to 10 and this d100 gives 1 to 100 as a single number. There is no 0 face and no separate tens die.

Example rolls and how to read the result

Real output from the roller. Rolls are random, so the same settings give different dice each time.

2d6, the default

Dice type d6, How many dice 2, Modifier 0

Rolls 6 and 2. Total 8, Dice sum 8, Average roll 4, Highest 6, Lowest 2

1d20+5 attack roll

Dice type d20, How many dice 1, Modifier 5

Roll 20. Total 25 (20 + 5), Dice sum 20

The Rolls list shows the natural 20 before the bonus, which is what matters for a critical hit.

2d20 for advantage or disadvantage

Dice type d20, How many dice 2, Modifier 0

Rolls 20 and 7. Highest 20, Lowest 7, Total 27

Take 20 with advantage or 7 with disadvantage, and ignore Total.

2d8-1 damage

Dice type d8, How many dice 2, Modifier -1

Rolls 8 and 3. Total 10 (11 − 1), Dice sum 11, Average roll 5.5

4d6 drop lowest for an ability score

Dice type d6, How many dice 4, Modifier 0

Rolls 6, 2, 3 and 5. Dice sum 16, Lowest 2

Subtract Lowest from Dice sum: 16 minus 2 gives a score of 14.

3d6

Dice type d6, How many dice 3, Modifier 0

Rolls 6, 2 and 3. Total 11, Average roll 3.67, Highest 6, Lowest 2

d100 percentile roll

Dice type d100, How many dice 1, Modifier 0

Roll 98. Total 98

2d6 probability chart

Two six-sided dice have 36 equally likely combinations. Totals near 7 come up far more often than the extremes.

Total	Combinations	Chance	Chance of this total or higher
2	1	2.78%	100%
3	2	5.56%	97.22%
4	3	8.33%	91.67%
5	4	11.11%	83.33%
6	5	13.89%	72.22%
7	6	16.67%	58.33%
8	5	13.89%	41.67%
9	4	11.11%	27.78%
10	3	8.33%	16.67%
11	2	5.56%	8.33%
12	1	2.78%	2.78%

Common dice rolls: minimum, maximum and average

How to set up frequently used rolls, and the range to expect from each.

Roll	Dice type	How many dice	Modifier	Minimum	Maximum	Average
1d20	d20	1	0	1	20	10.5
1d20+5	d20	1	5	6	25	15.5
2d6	d6	2	0	2	12	7
3d6	d6	3	0	3	18	10.5
1d8+3	d8	1	3	4	11	7.5
2d10	d10	2	0	2	20	11
1d12+4	d12	1	4	5	16	10.5
8d6	d6	8	0	8	48	28
1d100	d100	1	0	1	100	50.5
20d6	d6	20	0	20	120	70

Average = number of dice x (sides + 1) / 2, plus the modifier.

Advantage, disadvantage and 4d6 drop lowest by the numbers

Rolling two d20s and keeping the higher one raises the average from 10.5 to 13.825. Keeping the lower one drops it to 7.175. The chance of at least one natural 20 on two dice is 9.75%, compared with 5% on a single die, and the chance of both showing 20 is 0.25%. The same figures apply in reverse to natural 1s with disadvantage.

For ability scores, rolling four d6 and dropping the lowest die gives an average of about 12.24, against 10.5 for a straight 3d6. The roller does not drop dice for you, but Dice sum minus Lowest gives the answer in one subtraction.

The Average roll figure in the results is the mean of the dice you just rolled, not the theoretical average. Over a few dice it can sit well away from the expected value; rolling 20d6 once gave an average of 4.15 against an expected 3.5.

Limits of this dice roller

One die type per roll. For 1d8 + 1d6, roll each type separately and add the totals.
1 to 20 dice per roll. Larger pools need two or more presses.
Seven fixed dice: d4, d6, d8, d10, d12, d20 and d100. There is no d2, d3 or custom number of sides.
The modifier is a whole number added once to the total. Decimals are cut down to the whole part.
No dice notation box, exploding dice, rerolls, success counting or automatic keep-highest and drop-lowest.
No roll history. Each press replaces the previous result, so copy the Rolls list if you need a record.
The rolls come from a fast pseudo-random generator restarted with a fresh random value on each press. That is fine for games and teaching, but it is not a certified source for gambling or prize draws.

Using Dice Roller

1
Choose the Dice type: d4, d6, d8, d10, d12, d20 or d100.
2
Enter How many dice to roll together, from 1 to 20.
3
Type a Modifier if the roll has a flat bonus or penalty, for example 3 or -2. Leave it at 0 for a plain roll.
4
Press Roll and read each die in the Rolls list.
5
Use Total for the final result, or Highest and Lowest for advantage, disadvantage and drop-the-lowest rolls.

Questions people ask

Are the dice rolls fair?

Each die is drawn uniformly, so every face from 1 to the number of sides has the same chance, and each roll is independent of the last. Physical dice can be slightly uneven from wear or manufacturing; a virtual die has no such bias.

Can I roll a d6 and a d20 at the same time?

Not in one press. Pick one die type, roll, note the result, then switch type and roll again. The Modifier field can carry a fixed bonus but not the result of another die.

How do I enter a negative modifier?

Type a minus sign before the number, such as -2. The Total then shows the dice sum with the penalty taken off, and the breakdown reads, for example, 11 − 1.

How do I roll a percentile die?

Choose d100 and roll one die. You get a single number from 1 to 100, with each value having a 1% chance. To succeed on a roll-under check of 35%, you need 35 or lower.

Can I use this for Dungeons & Dragons?

Yes. It has the full set of standard polyhedral dice and handles attack rolls, saving throws, skill checks and damage with a flat bonus. Mixed-dice damage takes one roll per die type, and advantage means rolling two d20s and reading Highest.

What does a natural 20 mean?

It means the d20 itself landed on 20 before any modifier is added. Check the Rolls list rather than Total to see it: a Total of 20 made from a 15 and a +5 bonus is not a natural 20.

Why is my average roll different from the average in the table?

The table shows the long-run average. The Average roll in your result is just the mean of the few dice in that roll, so it varies. It gets closer to the table figure as you roll more dice.

What can I use if a board game die is missing?

Set Dice type to d6 and How many dice to the number the game uses, usually one or two. The Rolls list shows each die separately for games that need the individual faces, such as checking for doubles.

What is the chance of rolling doubles on two dice?

1 in 6, or 16.67%, on two d6: six of the 36 combinations are pairs. For any two dice of the same type the chance is one divided by the number of sides, so 5% on two d20s.