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About this tool
Split rent into envy-free shares from each housemate's room preferences and the total.
This rent splitter takes a total rent, a list of housemates and each person's preference score for every room, then tests every possible room assignment and keeps the one with the highest minimum score — the max-min rule — breaking ties by the highest total score. Rent is then divided in inverse proportion to how strongly each person rated the room they were given, rescaled so the individual shares add back to exactly the rent you entered. It is for a group moving into a flat with unequal rooms who want the split argued from numbers rather than from who spoke loudest.
Open Envy-Free Rent Splitter on AltFTool — it loads instantly in your browser.
Enter the Total rent, list housemates one per line under People, and fill 'Rooms and preference values' as 'Room | value by person 1 | person 2 | …', with each person's values totalling 100.
The result recomputes as you type: every permutation of people to rooms is scored, the assignment with the highest minimum score wins, and ties break on the highest combined score — press the 'Three people' chip under Examples to load a worked set.
Read the Person / Room / Preference / Suggested share table — shares run inversely to each person's score for their room and are rescaled to sum to the rent you entered — then Copy or Download it.
All permutations of people to rooms are enumerated, so the chosen match is optimal under the max-min rule, not a first guess.
The suggested amounts are rescaled to sum to the total rent you entered, so there is no rounding gap to argue about.
The table shows who got which room and the preference score that produced their share, so the group can check the logic rather than trust a number.
Each person distributes points across the rooms so that their own scores total 100 — for example 50 for the large room, 30 for the balcony room and 20 for the quiet room. Scores are personal and do not need to match anyone else's; what matters is the relative gap between rooms within one person's row.
It scores every possible assignment and picks the one where the worst-off person's preference score is as high as possible. With three people that is 6 assignments, with four it is 24 and with five it is 120; ties on the worst-off score are broken by the highest combined score across the group.
Because shares here are set inversely to the preference score for the assigned room, so a strong match lowers that person's amount and a weak match raises it. That is one defensible convention, not the only one — some groups prefer the opposite rule, where the most-wanted room costs the most, so agree on the direction before you use the output.
No — it is an informational decision aid, and the tenancy agreement is what actually binds you. Whoever is named on the lease is usually liable for the full rent regardless of any private split, so put the agreed shares in writing between housemates and take legal advice if the lease terms matter.