Odd-Sided Dice: d3, d5, d7, d9, and d100

Odd-sided dice are dice or dice procedures that provide an uncommon number of possible outcomes, such as d3, d5, d7, d9, or d100. The notation identifies the intended number of outcomes, but the physical object may use a special shape, repeated numbers, a paired-die method, or a written procedure to produce that result.

What the notation means

In the usual dice notation, the number after the letter d represents the number of possible face results in the model. A d3 therefore represents three outcomes, while a d7 represents seven. The notation is a rules shorthand; it does not prove that a particular physical object has that many faces or that every outcome occurs equally often.

Some games simulate an uncommon die with a more familiar die. For example, a d6 can be read in pairs to produce a d3, with 1–2, 3–4, and 5–6 assigned to the three results. The exact mapping belongs to the rules source and should be recorded with the entry.

d3, d5, d7, and d9

Odd-sided results are often produced by a simulation rather than by a regular polyhedral shape. A d3 may be simulated with a d6, and a d5 can be simulated with a d10 by pairing 1–2, 3–4, 5–6, 7–8, and 9–10. A d7 or d9 may use a larger die and a rejection or remapping procedure. If a method gives some results more often than others, it is not an equal-probability d7 or d9 model unless the rules explicitly define that distribution.

DICEWIKI records the method, the mapping, and any reroll instruction instead of treating the simulated die as a physical product. This distinction is important when comparing a game mechanic with a catalogue listing.

d100 and percentile results

A d100 or percentile roll commonly uses two d10s: one for tens and one for units. The pair creates results from 01 through 100 when the rules define 00 as 100. A single d10 marked 0–9 may also be used as part of the procedure. Readers should verify which die is the tens die and how 00 is interpreted before recording a result.

Physical shapes and fairness

An uncommon face count does not automatically describe a regular polyhedron, a particular material, or a fair physical die. A product may use numbering, symbols, repeated faces, or a special reading instruction. Record those properties separately. If an entry makes a claim about equal likelihood, cite the mathematical model or a documented test rather than inferring it from the label.

How to catalogue odd-sided dice

1. State the intended number of outcomes and the notation used.
2. Identify whether the result comes from a physical die, a die pair, or a simulation.
3. Document mappings, rerolls, rejection rules, and the treatment of zero.
4. Separate face count, markings, material, and fairness evidence.
5. Link the game rule, product source, or test method supporting the claim.

Related DICEWIKI pages

Read percentile dice, dice notation, polyhedral dice, and how to read dice. For the mathematical model, see dice probability basics.

Sources and editorial notes

1. D&D Beyond Basic Rules: Playing the Game, for the attributed examples of d3, d100, and percentile procedures.
2. DICEWIKI editorial taxonomy, for separating a notation, a simulation method, and a physical product.