Weighted Random Number Generator
Give each number its own weight so some outcomes are more likely than others, then draw.
Weighted Random Number Generator
Weighted draw
Outcomes and weights
Higher weights are more likely. Values can be numbers or words.
How many draws
How to use the weighted generator
- List each outcome with a weight, one per line, as value then weight.
- Set how many draws you want.
- Generate. Outcomes appear in proportion to their weights.
About Random Nr's Weighted Random Number Generator
The weighted random number generator lets you give each number its own weight, so some outcomes come up more often than others when you draw. Enter your values and their weights, draw, and Random Nr picks in proportion to the weights, which models loaded dice, prize tables and any choice where the odds are not meant to be equal.
How weights become probabilities
A weight is just a relative share. The tool adds all the weights and each outcome's chance is its own weight over that total, so the numbers do not need to add to 100.
| Outcome | Weight | Chance | Expected in 1000 draws |
|---|---|---|---|
| Common | 70 | 70% | 700 |
| Uncommon | 20 | 20% | 200 |
| Rare | 9 | 9% | 90 |
| Legendary | 1 | 1% | 10 |
This is exactly how a game loot table works: a weight of 70 against a total of 100 means that outcome turns up about 700 times in a thousand draws, while the legendary at weight 1 appears about 10 times.
How the weighted draw is made
The tool lays every outcome along a line as long as the total weight, picks a random point on that line with the cryptographic source, and sees which outcome the point lands in. Bigger weights cover more of the line, so they are hit more often, while the smallest weights still get their fair share over many draws. Draw once for a single result, or thousands of times to watch the proportions settle onto the table above.
What weighted draws are used for
Loot tables and item drops, biased dice, weighted raffles where some entrants hold more tickets, and any simulation where outcomes are not equally likely all need weighting. For an even draw where every outcome has the same chance, use the random number generator, and for a repeatable weighted draw, combine the idea with the seeded generator.
More number generators
Frequently asked questions
How do I set the weights
Write one outcome per line as value then weight, for example 1 : 5. Higher weights are more likely.
Can outcomes be words
Yes. Values can be numbers or words, so you can weight names, prizes or labels as easily as numbers.
Do the weights need to add to 100
No. Weights are relative, so 5, 3 and 1 work just as well as percentages. The tool normalises them for you.
Can I draw many at once
Yes, up to 1000 draws, which is a quick way to see how the weighting plays out.
Is it free
Yes, free and with no sign up.
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For an even draw with no weighting, use the random number generator, or a repeatable draw with the seeded generator.