Split Rent Calculator
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A split rent calculator for housemates: by room size, by income or evenly, and it always adds up to the rent.
- Type the rent, and choose whether to split it by room size, by income or equally.
- List everybody with their room size — or their income — and the days they are there if it is not the whole month.
- Read each person's share. They add up to the rent exactly, so there is nothing left over to argue about.
Any unit, as long as everybody uses the same one.
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About this tool
Rooms in a shared house are never the same size, which is why splitting the rent down the middle starts an argument. This is a split rent calculator that does the arithmetic three ways — a rent calculator roommates can actually agree on, because everybody can see where the numbers came from. By room size is the usual answer, and the one most people mean by how to split rent fairly. It works out a price per unit of floor space across the whole place, charges each person for their own bedroom at that price, and divides the shared space — kitchen, sitting room, hallway — equally between everyone. That last part is what a naive split rent by room size gets wrong: the person with the big bedroom should pay more for the bedroom, not more for a sofa you both use equally. Any unit works as long as everybody uses the same one, so split rent by square footage comes out to exactly the same shares as square metres. Rent split by income is the other common arrangement, and an even split is still here for a flat where the rooms genuinely do match. Whether you split rent with roommates in a two-bed or six people in a shared house, somebody there for only part of the month can be counted for the days they are — and the shares always add up to the rent you typed, to the last penny.
Frequently asked questions
How should we split rent when the rooms are different sizes?
Charge each person for their own room, and split everything you share equally. That is what "by room size" does here: it takes the rent over the total floor area to get a price per square metre, bills each bedroom at that price, then divides the shared space between everybody. The usual mistake is to split the whole rent in proportion to bedroom size alone, which charges the person with the bigger room more for the kitchen and the sofa as well — and those are not bigger for them. If you leave the shared space empty it does exactly that simpler sum, so you can see the difference between the two.
Does it matter whether I measure in square metres or square feet?
No, as long as everyone is measured the same way. Every method here works on ratios — your room against the whole floor — so the unit cancels out and the shares are identical. Measure in square metres, square feet, paces or floorboards; what breaks it is one room in feet and another in metres. If you do not know the areas, pacing each room out and multiplying is close enough: a few per cent of error in a room moves somebody's share by pennies.
What if somebody moves in halfway through the month?
Put the days they are actually there in the Days column and leave everybody else on the full month. Their share shrinks in proportion — and everybody else's grows, because the landlord still wants the whole rent. That is worth saying out loud before you show the table to the house: the total is always the rent you typed, so a short stay for one person is money the others make up. If what you actually want is one person's part-month rent on its own, that is a different sum: put them in on their own and the answer is theirs alone.
Should we split rent by income instead?
Some houses do, and it is the fairest arrangement in a house where one person earns three times another and the rooms are much the same. It is also the one that needs the most trust, because everybody has to say what they earn and believe the others. Rent split by income here is straight proportion: twice the income, twice the share. Nothing stops you combining the ideas by hand — work it out by room size, then by income, and settle somewhere between the two.
Do the shares really add up to the rent exactly?
Yes, to the penny, and that is deliberate. Three shares of a £1,400 rent will not divide evenly, so there is always a penny or two left over once each share is rounded. Rather than rounding each one and handing you a total that is a few pence out, the leftover pennies go to whoever was rounded down hardest. So the column always sums to what you typed, and nobody has to work out who covers the difference.
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