Weighted random picker

Pick a random item from a list, giving each entry a different probability defined by a weight. Ideal for a raffle, a prize wheel or distributing prizes. The draw happens entirely in your browser.

Example:
The weight sets the relative probability: an entry with a weight of 5 is 5 times more likely to be picked than one with a weight of 1. Without ":weight", an entry gets a weight of 1.

How it works

A standard random draw gives every entry exactly the same chance of being chosen. A weighted draw lets you reflect different probabilities instead: for example, a raffle where the grand prize should be rarer than the consolation prizes, or assigning tasks while giving more weight to some people. The draw uses the browser's pseudo-random number generator, applied to the cumulative sum of each entry's weight.

How exactly are the probabilities calculated?

Each entry takes up a portion of a segment whose length is proportional to its weight: with weights 1, 2 and 5, the total is 8, so the first entry has a 1/8 chance, the second 2/8 and the third 5/8. A random number is then drawn within this segment to determine which entry is selected.

Can I use decimal weights or weights on very different scales?

Yes, weights can be decimal numbers (for example 0.5 or 2.75) and there is no limit on the gap between the smallest and largest weight: only the ratio between weights matters in determining the relative probabilities.

None of your entries is sent to a server: the draw is calculated locally, in your browser.