1D38

1D38, commonly written 1d38, refers to rolling a single 38-sided die. In dice notation, the first number indicates how many dice are rolled, and the second indicates how many faces the die has. Therefore, a 1d38 roll produces an integer outcome from 1 to 38, with each result having equal probability. The distribution is uniform, so each face has a probability of 1/38 (about 2.63%).

Physical form and availability follow from the rarity of 38-faced dice. Such dice exist and are produced by some specialized manufacturers for niche games or novelty purposes, but they are far less common than standard dice like d4, d6, d8, d10, d12, d20, or d100. When used in play, a 38-sided die provides a broader range of outcomes than typical polyhedral dice.

Usage in games and calculations. A 1d38 roll is most often used in tabletop role-playing games or probability demonstrations where a larger result space is useful. To adapt a 1d38 result to another scale, players commonly employ simple transformation rules or reroll schemes to fit a target range. For example, to map to a smaller range, uneven portions may be discarded or rerolled to achieve a uniform distribution over the desired interval.

See also. Dice notation, polyhedral dice, randomness in gaming, probability distributions.