1, 100 Dice Wheel
A d100 is the percentile die of tabletop gaming, and SpinyWheel's 1–100 Dice Wheel is the same roll without the dice. All 100 numbers sit on the wheel at 1 percent each. Game masters, loot tables, and anyone whose d100 rolled under the sofa spin it.
What is a d100 and how do you roll one?
A d100 produces a whole number from 1 to 100 with every result equally likely. Most tables roll it as two ten-sided dice, one read as tens and one as units, with a double zero counted as 100. A single hundred-sided die exists but rolls badly.
The two-dice method needs colour coding or a marked tens die, because 3 and 7 can mean 37 or 73 depending on which you decide reads first. Arguments over that ordering are common enough that many groups keep a dedicated percentile pair. The wheel removes the reading step: the number that lands is the number.
Threshold math without a conversion table
Percentile is popular because 1 number equals 1 percent, so any target on the wheel converts to odds in your head. No division, no lookup:
| Target | Numbers that hit | Chance |
|---|---|---|
| Exactly 1 | 1 | 1% |
| Under 15 | 1 to 14 | 14% |
| 50 or less | 1 to 50 | 50% |
| 96 or higher | 96 to 100 | 5% |
| Exactly 100 | 100 | 1% |
Roll-under systems build entire rulesets on that convenience. Call of Cthulhu gives a character a skill rated as a percentage and asks you to roll at or under it, so a 65 in Library Use is literally a 65 percent chance. Nothing has to be converted, which is why percentile survives in systems that want probability legible at the table.
Loot tables, encounters, and wild magic
The 1 percent slice is the reason d100 owns random tables. A hundred-row table gives every entry its own result with nothing left over, and a designer can widen any row by assigning it a range. Dungeons & Dragons fifth edition uses exactly that structure for its wild magic surge table, where each surge occupies its own numbered band.
Encounter tables, treasure hoards, critical hit and fumble charts, and random NPC generators all work the same way. Weighting is built into the row widths rather than bolted on: a result spanning 01 to 40 is common, a result on 00 is once in a hundred, and the table itself shows the distribution at a glance.
When the 1–100 Dice Wheel beats a physical die
Remote play is the obvious case. A wheel on a shared screen is visible to everyone at once, so no one is trusting a roll they cannot see, and no one is typing a result into chat and hoping it reads as honest.
The second case is a table with no percentile dice in the bag, which happens more than anyone admits. A d20 cannot fake it and two d6 produce a hump rather than a flat line. For rolls of a different shape, the 1-2-3 Dice Block Wheel covers three outcomes, and the how-to guide walks through building a custom table range like 1 to 12 or 1 to 30.
FAQ
For practical purposes yes, and the distributions are identical. Two ten-sided dice with one designated as tens produce a flat 1 to 100 spread, and a double zero is read as 100 by convention. The single hundred-sided die, sometimes called a Zocchihedron, gives the same range but rolls for an awkwardly long time before settling.
Take the tens die as the first digit and the units die as the second, so a 4 and a 2 make 42. Agree which die is which before rolling, since the same pair also reads as 24. SpinyWheel's 1, 100 Dice Wheel skips the convention entirely and shows the finished number.
Yes, and the arithmetic stays trivial. A skill rated 65 succeeds on any result from 1 to 65, which is a 65 percent chance because each number holds exactly 1 percent. Roll-over targets work the same in reverse: needing 80 or higher is a 21 percent chance, covering 80 through 100.
One percent for any repeat, since the second spin has one chance in a hundred of matching the first. A named number landing twice running happens once per 10,000 pairs. Seeing all 100 numbers at least once takes roughly 519 spins on average, because late in a run most results are ones already seen.
Spin it, read the number, and get on with the table.