Roll a d100
A percentile dice roller: one tap gives a fair number from 1 to 100.
Tap roll
How to use the roll a d100
- Tap Roll or press the space bar to roll a d100.
- The result is a number from 1 to 100, with your recent rolls underneath.
- For a bonus or penalty, type it in the box, for example d100-10.
How percentile dice work
On a real table a d100 is usually two ten-sided dice: one marked 00 to 90 for the tens and one marked 0 to 9 for the units. Add them together, and read 00 with 0 as 100. flipj does the same thing in one step and gives every number from 1 to 100 exactly the same 1% chance.
What d100 rolls are used for
- Wild Magic Surge: a D&D wild magic sorcerer rolls on a d100 table to see what happens.
- Random tables for encounters, loot, weather and rumours are often written for a d100.
- Call of Cthulhu and other percentile systems: roll equal to or under your skill to succeed.
d100 odds and averages
Every number has a 1% chance and the average roll is 50.5. Rolling 50 or under is exactly a 50% chance, so a d100 is also a handy fair "coin" for any percentage, like a 30% chance of rain.
flipj uses your browser's built-in cryptographic random number generator (crypto.getRandomValues), the same source browsers use for encryption keys. We also avoid "modulo bias", a subtle flaw where some results come up slightly more often than others. Every result is generated on your device, so nothing you enter is sent to us.
Questions
Is a d100 the same as a random number from 1 to 100?
Yes. Each number from 1 to 100 is equally likely.
What is the average roll on a d100?
50.5.