How to read a d1000
Roll three d10s and call them hundreds, tens and units before you roll. 4, 0 and 7 is 407. 0, 0 and 0 together is 1000, not zero. It is the same trick as percentile dice, with one more die.
With a d100
If you have a hundred-sided die, roll it with one d10. The d10 gives the hundreds (0 means none) and the d100 gives the rest: a 3 and a 58 is 358, and a 0 and a 100 is 100. On the 3D table, the d100 setting switches between two d10s and one 100-sided die, and a d1000 follows it.
Where the d1000 shows up
- Huge random tables. Fan-made lists of a thousand trinkets, rumors or wild magic surges.
- Rare events. "One chance in a thousand" is a d1000 roll of 1.
- Big numbers in one go. A population, a treasure hoard or a distance, when a d100 is too small.
Every number is equally likely
Each die is fair and each one fills its own place, so every number from 1 to 1000 comes up exactly one time in a thousand. Rolling a number or lower is just that number in tenths of a percent: 250 or lower is 25%, 37 or lower is 3.7%, and 1 alone is 0.1%.
How long until a 1 in 1000 comes up
A one-in-a-thousand result is rarer than it sounds. The chance of seeing a particular number, say 1, at least once:
| Rolls | Chance |
|---|---|
| 10 | 1.0% |
| 100 | 9.5% |
| 250 | 22.1% |
| 500 | 39.4% |
| 693 | 50.0% |
| 1,000 | 63.2% |
| 2,000 | 86.5% |
| 3,000 | 95.0% |
It takes 693 rolls for an even chance, and a thousand rolls still miss it more than a third of the time. The d100 page has the same table for one in a hundred, and the dice calculator works out any other roll.
Questions
What does 1d1000 mean?
One roll from 1 to 1000, every number equally likely. It is written d1000 or 1d1000, and is usually made with three ten-sided dice read as hundreds, tens and units. The Dice Notation Guide covers the rest.
Does a real d1000 exist?
Rarely. A few makers have designed thousand-faced dice, but the faces are tiny and the die rolls like a ball. At the table, almost everyone rolls three d10s instead, and this page gives you the result in one tap.
How do I roll a d1000 with d10s?
Pick which die is hundreds, which is tens and which is units before you roll, then read them in order: 6, 2 and 9 is 629. Three zeros read 1000, never zero.
Is 3d10 the same as a d1000?
No. Adding three d10s gives 3 to 30, with 16 and 17 the likeliest (7.5% each) and a 3 only 0.1%. Reading them as digits gives 1 to 1000, each exactly 0.1%. A thousand-entry table needs the second.
What is the average roll on a d1000?
500.5, halfway between 1 and 1000. A roll of 500 or lower comes up exactly half the time.
Is this d1000 roller random and fair?
Yes. Each roll comes from your browser's cryptographic random number generator, with no bias towards any number. Every result from 1 to 1000 is exactly 1 in 1000.