Fair Division Tool
Distribute items fairly between people.
Built and maintained by Paul Clark, Redmoon Software · Last checked
The Fair Division Tool spreads a set of items across a group of people as evenly as possible, using a random tie-break when things don't split cleanly. Use it for sharing chores, splitting loot, dividing tasks, or handing out shifts so no one feels shortchanged. Unlike a raffle, everyone walks away with a fair share rather than one winner taking all.
Enter. List the items to share and the people who will receive them.
Click Divide to see a result.
Options
Recent results
- No history yet.
How it works
- Enter. List the items to share and the people who will receive them.
- Divide. Click Divide to spread the items as evenly as possible.
- Review. See who got what, including any randomly assigned leftovers.
- Redo. Divide again for a fresh allocation if you want a different split.
About the Fair Division Tool
How the items are dealt
The item list is shuffled and then dealt round-robin across the people — first item to the first person, second to the second, and so on, wrapping around. That guarantees the counts are as even as arithmetic allows: with eight items and three people, somebody gets three and the others get two or three.
There is a detail worth knowing about who gets the extra. The items are shuffled but the people are not — they are dealt in the order you typed them. So when the division is uneven, the surplus always goes to whoever is at the top of your list. If that matters, shuffle your people list before pasting it, or reorder it between rounds.
Equal counts are not equal value
This divides by number of items, and nothing else. Three items each is only fair if the items are comparable — and for the cases people most often reach for a division tool, like splitting an estate or dividing chores, they are conspicuously not.
For genuinely unequal items, the classical answer is not a random deal at all: it is a procedure like "one person divides, the other chooses", or taking turns picking. Use this tool when the items really are interchangeable, and a turn-based method when they are not. There is more on the uneven case here.
What the output looks like
- Both lists are saved in this browser as you type, so a reload does not lose your setup.
- There is no seed, so a division cannot be reproduced — copy the result if it matters.
- The result is grouped per person, which is the form you want to paste into a message.
- Only the last ten divisions are kept.
Frequently asked questions
What if the items don't divide evenly?
Any leftovers are assigned at random, so every person's expected value comes out equal over time.
How is this different from a raffle?
A raffle gives everything to one winner. Fair division spreads the items so everyone gets at least one when there are enough to go around.
Are the random tie-breaks unbiased?
Yes. The tool uses your browser's Web Crypto API for the random assignment, so no person is favored.
Is my list of items and people private?
Yes. Everything is processed in your browser and works offline, so nothing you enter is sent to a server.
Related randomizers
Further reading
- Dividing things up when the numbers don't come out even
Splitting 17 items between 4 people means somebody gets a fifth one. Here is how a fair division tool deals items out at random, why it splits by count rather than value, and the one thing you should do to your list of people first.
- Who gets which prize? Let chance decide — and show your work
Picking winners is the easy half of a prize draw. The fight starts when someone has to decide who gets the good prize and who gets the mug. A random prize assigner matches people to prizes in one shuffle nobody chose.
- A chore roster that actually feels fair (and stops the arguments)
The same person always ends up on bathroom duty. Here's how a random chore roster — fresh shuffle each day, rotated across the week — spreads the jobs nobody wants without anyone keeping score, and how it handles having more chores than people.
- Matching two lists fairly: zip prizes, tasks, and partners at random
Assigning a list of people to a list of prizes, chores, or projects sounds trivial until you do it by hand and someone notices a pattern. Here's how a two-list matcher zips one list to a shuffled copy of another, what happens when the lists are different lengths, and when to reach for a different tool.