Online DiceRoll 1 custom-sided die online
1 custom die · your chosen range
Thirteen possibilities, one custom answer ♾️
An awkwardly sized list is a good reason to use a custom die. Set its sides to the number of entries, then roll one row number directly. Your options get to keep their own length.
♾️ Any-Sided Dice Roller - Type a Number and Let Geometry Cope
Need D13, D37 or D7318? Enter the number of sides and roll. The browser does the counting so you do not have to construct an alarming physical object.
A 7318-sided die is allowed. Whether it is emotionally necessary is outside the scope of this tool.
What custom dice are good for
Exact-size lists. If your table has 17 cities, 43 names or 211 weird artifacts, matching the range directly avoids rerolls and conversion rules.
| N sides | Results 1 through N |
|---|---|
| Chance per result | 1/N |
| Recommended noodles | Not mathematically defined |
Large side counts create more possible outcomes, not "more random" randomness. D9999 can still roll something boring.
Conventional geometry: D20 · D30 · D100
The list length gets to choose the die
- A random table with exactly as many rows as your list.
- Choosing from 37 names, 83 encounters or 365 prompts.
- Classroom exercises and probability experiments.
- Homebrew games where standard dice sizes are arbitrary.
Pick one of thirteen names
Number thirteen possible names from 1 to 13 and set the sides field to 13. The worked example selects the seventh name. Every name occupies one equally weighted entry; adding an extra name later means changing the side count as well.
⚙️ Example setup: 1 dice × 13 sides
Raw sum7 = 7
Zero-based lists need one small conversion
The range starts at 1. If your list uses indices 0–12, subtract one from the result before looking up the entry. Decide on that convention first so the first and last options are both reachable.
Every name has a place in the range
With this example setup, each numbered row has a 1/13 chance (7.69%) in the uniform-die model. One die is a flat choice across the range, so the selected row is the useful result.
Set the range to the actual list
The names stay numbered 1–13 in this example. The custom field accepts whole numbers from 2 to 9999, so another list length can keep the same direct row-number procedure.