How to split rent fairly by room size, with a worked example
Short answer
Decide how much of the rent pays for shared space (kitchen, living room, bathroom), often half, and split that part equally. Split the rest by each bedroom's floor area: a room's share = its area / total bedroom area. Each person pays their equal shared part plus their room part. Add a little for a private bathroom or balcony if your group agrees.
Copy-paste code
Worked example: $2,400 a month, 3 rooms (16, 12 and 10 square metres)
Shared half: $1,200 / 3 = $400 each
Room half: $1,200 split by area (16 + 12 + 10 = 38 m2)
Room A: 16/38 x 1,200 = $505.26
Room B: 12/38 x 1,200 = $378.95
Room C: 10/38 x 1,200 = $315.79
Monthly rent per person:
A: 400 + 505.26 = $905.26
B: 400 + 378.95 = $778.95
C: 400 + 315.79 = $715.79 (total $2,400.00)
Spreadsheet: =shared/COUNT(people) + area/SUM(areas)*room_partGood to know
Round to the cent and give any leftover cent to one person so the shares add up to the rent exactly.
Write the split down and agree on it before anyone moves in; it is much harder to change later.
Kittyfern: Split group costs, settle up fast
from $3.99Kittyfern splits by shares, so you can enter each room's area as its share, then track who paid the rent and bills and settle up with the fewest payments. Free for one group; Pro adds monthly roommate bills.
Secure checkout · 14-day fix-or-refund if it doesn't work as described (terms)Questions
What share should be the shared space?
There is no rule; half is a common starting point. Use more if the shared rooms are large, less if bedrooms are most of the flat.
What about bills?
Utilities are usually split equally, since everyone uses the kitchen, hot water and internet.
Do I need an app?
No. A spreadsheet works; Kittyfern's shares split does the arithmetic and the monthly settle-up in your browser, free for one group.
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