dice-app.com

D100 Dice Roller

A d100 is almost never a hundred-sided object. It is two d10s read together, one marked in tens and one in units, giving a result from 00 to 99 with double zero read as 100. Solid hundred-faced balls do exist, most famously the Zocchihedron, but they roll for so long that nobody uses them in play.

Press Roll to throw the dice.

Total —

Number of dice
Modifier

Press Space to roll again. Type notation like 2d6+3 or 4d6dl1 straight into the box.

Recent rolls

  • No rolls yet.

A d100 gives 100 results numbered 1–100. On a fair die every face is equally likely, so any single result comes up 1% of the time. Rolls run from 1 to 100, the average is 50.5, and the standard deviation is 28.87. It is normally rolled as two ten-sided dice, one read as tens and one as units.

Minimum
1
Maximum
100
Mean
50.5
Median
50.5
Std deviation
28.87
Chance per face
1%

d100 probability

One die is flat. There is no curve and no middle to aim for, because each face has exactly one way to come up out of 100 possible results, so nothing is more likely than anything else. Add a second die and that changes immediately: totals start piling up in the middle. The dice probability guide works through why.

Bar chart of the 1d100 distribution. Totals run from 1 to 100. The tallest bar is 1 and 2 and 3 and 4 and 5 and 6 and 7 and 8 and 9 and 10 and 11 and 12 and 13 and 14 and 15 and 16 and 17 and 18 and 19 and 20 and 21 and 22 and 23 and 24 and 25 and 26 and 27 and 28 and 29 and 30 and 31 and 32 and 33 and 34 and 35 and 36 and 37 and 38 and 39 and 40 and 41 and 42 and 43 and 44 and 45 and 46 and 47 and 48 and 49 and 50 and 51 and 52 and 53 and 54 and 55 and 56 and 57 and 58 and 59 and 60 and 61 and 62 and 63 and 64 and 65 and 66 and 67 and 68 and 69 and 70 and 71 and 72 and 73 and 74 and 75 and 76 and 77 and 78 and 79 and 80 and 81 and 82 and 83 and 84 and 85 and 86 and 87 and 88 and 89 and 90 and 91 and 92 and 93 and 94 and 95 and 96 and 97 and 98 and 99 and 100 at 1% each. 1: 1% 2: 1% 3: 1% 4: 1% 5: 1% 6: 1% 7: 1% 8: 1% 9: 1% 10: 1% 11: 1% 12: 1% 13: 1% 14: 1% 15: 1% 16: 1% 17: 1% 18: 1% 19: 1% 20: 1% 21: 1% 22: 1% 23: 1% 24: 1% 25: 1% 26: 1% 27: 1% 28: 1% 29: 1% 30: 1% 31: 1% 32: 1% 33: 1% 34: 1% 35: 1% 36: 1% 37: 1% 38: 1% 39: 1% 40: 1% 41: 1% 42: 1% 43: 1% 44: 1% 45: 1% 46: 1% 47: 1% 48: 1% 49: 1% 50: 1% 51: 1% 52: 1% 53: 1% 54: 1% 55: 1% 56: 1% 57: 1% 58: 1% 59: 1% 60: 1% 61: 1% 62: 1% 63: 1% 64: 1% 65: 1% 66: 1% 67: 1% 68: 1% 69: 1% 70: 1% 71: 1% 72: 1% 73: 1% 74: 1% 75: 1% 76: 1% 77: 1% 78: 1% 79: 1% 80: 1% 81: 1% 82: 1% 83: 1% 84: 1% 85: 1% 86: 1% 87: 1% 88: 1% 89: 1% 90: 1% 91: 1% 92: 1% 93: 1% 94: 1% 95: 1% 96: 1% 97: 1% 98: 1% 99: 1% 100: 1%
Every face of a d100 is equally likely, so the chart is flat.
Exact odds for every result on a d100.
Total Ways Probability This or lower
1 1 1% 1%
2 1 1% 2%
3 1 1% 3%
4 1 1% 4%
5 1 1% 5%
6 1 1% 6%
7 1 1% 7%
8 1 1% 8%
9 1 1% 9%
10 1 1% 10%
11 1 1% 11%
12 1 1% 12%
13 1 1% 13%
14 1 1% 14%
15 1 1% 15%
16 1 1% 16%
17 1 1% 17%
18 1 1% 18%
19 1 1% 19%
20 1 1% 20%
21 1 1% 21%
22 1 1% 22%
23 1 1% 23%
24 1 1% 24%
25 1 1% 25%
26 1 1% 26%
27 1 1% 27%
28 1 1% 28%
29 1 1% 29%
30 1 1% 30%
31 1 1% 31%
32 1 1% 32%
33 1 1% 33%
34 1 1% 34%
35 1 1% 35%
36 1 1% 36%
37 1 1% 37%
38 1 1% 38%
39 1 1% 39%
40 1 1% 40%
41 1 1% 41%
42 1 1% 42%
43 1 1% 43%
44 1 1% 44%
45 1 1% 45%
46 1 1% 46%
47 1 1% 47%
48 1 1% 48%
49 1 1% 49%
50 1 1% 50%
51 1 1% 51%
52 1 1% 52%
53 1 1% 53%
54 1 1% 54%
55 1 1% 55%
56 1 1% 56%
57 1 1% 57%
58 1 1% 58%
59 1 1% 59%
60 1 1% 60%
61 1 1% 61%
62 1 1% 62%
63 1 1% 63%
64 1 1% 64%
65 1 1% 65%
66 1 1% 66%
67 1 1% 67%
68 1 1% 68%
69 1 1% 69%
70 1 1% 70%
71 1 1% 71%
72 1 1% 72%
73 1 1% 73%
74 1 1% 74%
75 1 1% 75%
76 1 1% 76%
77 1 1% 77%
78 1 1% 78%
79 1 1% 79%
80 1 1% 80%
81 1 1% 81%
82 1 1% 82%
83 1 1% 83%
84 1 1% 84%
85 1 1% 85%
86 1 1% 86%
87 1 1% 87%
88 1 1% 88%
89 1 1% 89%
90 1 1% 90%
91 1 1% 91%
92 1 1% 92%
93 1 1% 93%
94 1 1% 94%
95 1 1% 95%
96 1 1% 96%
97 1 1% 97%
98 1 1% 98%
99 1 1% 99%
100 1 1% 100%

When you'd roll a d100

Percentile rolls suit two situations: fine-grained skill checks and long tables. Systems that rate a skill as a percentage ask you to roll under it, so the number on your sheet is the number you need. Game masters also lean on d100 for tables with dozens of entries, because a hundred slots gives room to make rare results genuinely rare without inventing new dice.

Common uses

d100 questions

How do you roll a d100 with two dice?

Pick one d10 as the tens digit and one as the units, ideally a set where the tens die is printed 00 to 90. Roll both, read tens first, then units. Zero and zero is 100, not zero, and everything else reads exactly as printed.

What is a Zocchihedron?

A solid hundred-sided die designed by Lou Zocchi, sometimes called a golf ball. It is roughly spherical with a hundred small flattened faces and a weight inside to help it stop. It rolls for an uncomfortably long time, which is why two d10s remain standard.

Which games use percentile dice?

Call of Cthulhu, Warhammer Fantasy Roleplay and RuneQuest all build their skills as percentages and ask you to roll under them. The Warhammer 40,000 role-playing games starting with Rogue Trader use the same approach. Percentile tables also appear in games that otherwise use a d20.

Is rolling under or over better on a d100?

Neither is better, they are just different conventions. Roll-under systems put the target on your character sheet, so a higher skill is easier to read at a glance. Roll-over systems set a difficulty number instead. Check which one your game uses before adding any modifiers.