Rent split calculator by room size
Enter the monthly rent, the number of bedrooms and the size of each bedroom. Then choose how much of the rent pays for the shared space. This page splits that shared part equally, splits the rest by bedroom area, and shows what each person pays. The parts always add up to the rent exactly.
Result
| Person | Room (m²) | Shared part | Private part | Pays |
|---|---|---|---|---|
| Person 1 | 16 | 60.00 | 120.00 | 180.00 |
| Person 2 | 12 | 60.00 | 90.00 | 150.00 |
| Person 3 | 8 | 60.00 | 60.00 | 120.00 |
| Total | 36 | 180.00 | 270.00 | 450.00 |
Split evenly with no room sizes, the same rent would be about 150.00 each.
Five fair ways to split rent with roommates
No single method is fair for every flat. The right one depends on how different the rooms are and what the group values. These are the methods people use most:
- Equal split. Divide the rent by the number of people. It is quick and it works well when the bedrooms are about the same. It feels unfair as soon as one room is clearly bigger or better.
- By room area only. Each person pays in proportion to the floor area of their bedroom. It is simple, but it over-charges the person in the big room. They do not use more of the kitchen or the living room than anyone else.
- Two passes, shared plus private. This is what the calculator above does. A part of the rent pays for the shared space and everyone pays that part equally. The rest pays for the bedrooms and follows room size. Most groups find this the fairest result.
- Weights for extras. A private bathroom, a balcony or a parking space has a value that floor area does not show. Add some square metres to that room as a bonus, for example 4 m² for a private bathroom. The person with the extra then pays a little more.
- By income. Some couples and families split by what each person earns, so that rent takes the same share of each income. This is a personal choice, not a rule about the flat. Use it only when everyone agrees to share their income figures.
How to choose the shared space percentage
The shared space part is the share of the rent that pays for rooms everyone uses: the kitchen, the living room, the hallway and any shared bathroom. A good starting point is the share of the floor area those rooms take up. If the flat is 90 m² and the bedrooms add up to 36 m², the shared space is 54 m², which is 60% of the flat. In practice many groups pick a number between 30% and 50%, because the private bedroom is what most people value most.
A higher percentage brings everyone closer to an equal split. A lower percentage makes room size matter more. At 100% the split is fully equal, and at 0% it follows room size only. Try two or three values above and pick the one the whole group can accept.
A worked example
Three friends rent a flat for 450 a month (the currency does not matter). The bedrooms are 16 m², 12 m² and 8 m², so the bedrooms add up to 36 m². They agree that 40% of the rent pays for the shared space.
The shared part is 40% of 450, which is 180. Each person pays a third of that: 60. The private part is the other 270. The 16 m² room is 16 of the 36 m², so that person pays 120 of it. The 12 m² room pays 90 and the 8 m² room pays 60.
| Room | Shared part | Private part | Pays |
|---|---|---|---|
| 16 m² | 60 | 120 | 180 |
| 12 m² | 60 | 90 | 150 |
| 8 m² | 60 | 60 | 120 |
| Total | 180 | 270 | 450 |
An equal split would be 150 each. With the two-pass method, the person in the largest room pays 30 more and the person in the smallest room pays 30 less. The numbers rarely divide this cleanly. When they do not, the calculator gives the odd minor unit to the first person in the list, so the total still matches the rent.
What to agree before you sign the lease
Most rent arguments start with a rule that nobody wrote down. Agree these points before the first month and keep them where everyone can see them:
- The method and the shared space percentage, and who gets which room.
- How you split the deposit, and how you share any deductions when you move out.
- Whether bills such as electricity, water and internet are split equally or by some other rule.
- Who pays the landlord, on which day, and how the others pay that person back.
- What happens when someone moves out early or a new person moves in.
Review the split when something changes, for example when a room gets a new air conditioner or someone starts to work from home all day.
Keep track after the first month
The rent is the same every month, but the bills, the shopping and the repairs are not. One person pays the internet, another buys cleaning supplies, and a third pays the plumber. After a few months nobody is sure who owes whom. Splitty keeps that running record for a shared home. Everyone adds what they paid, everyone sees the same balances, and the settle-up screen nets the balances, so each person usually makes one payment.
For a one-off bill, use the bill split calculator. For a full guide to sharing a home, read splitting expenses with roommates. You can find every calculator on the tools page.