A couple sharing one room: per room, per person, or both?
There are three common answers, and each has a real argument. The hybrid (shared space per person, bedroom per room) is the one most households settle on, and the calculator shows why.
Kitchen, living room, shared bath. The rest of the rent follows each room.
Closet, light, noise
Closet, light, noise
Weights you agree on
The link holds the whole split. Nothing is stored on our server until you make it a household.
The working, room by room
| Room | People | Weight | Shared part | Room part | Pays |
|---|---|---|---|---|---|
| Couple | 2 | 140 × 1 | $633.33 | $501.89 | $1,135.22 |
| Roommate | 1 | 125 × 1 | $316.67 | $448.11 | $764.78 |
| Total | 3 | $950.00 | $950.00 | $1,900.00 |
Weight = floor area × the room’s multiplier (private bath and factors). Unrounded parts are shown; the “Pays” column is rounded to cents so it adds up exactly.
The numbers, step by step
A couple and one roommate rent a $1,900 two-bedroom with a large living room, so the household treats half the rent as shared space. The couple’s room is 140 sq ft; the roommate’s is 125.
- Couple pays $1,135.22, $567.61 each: 1.06× average floor area, 2 people share the common space.
- Roommate pays $764.78: 0.94× average floor area.
- Total: $1,900.00, exactly the rent.
Names and amounts are samples. Change any number in the calculator above and the result updates.
A fairness test you can run together
Fair-division research calls a split envy-free when each person feels they got the best piece “in her own estimation”, as Francis Su puts it. Ask: at these prices, would anyone rather swap rooms? If not, nobody envies anyone. Bid mode makes that a guarantee.
Keep it running
Turn this into a household: rent posts at the agreed split each month, bills split by days home, and housr works out who owes whom. Roommates join with a link and a name.
Make it a householdWhen this split is fair, and when it isn’t
Fair when
- Per person (three equal thirds) ignores that the couple has one bedroom between two. The hybrid only charges “per person” for the space everyone shares.
- Per room (two equal halves) ignores that two people use the kitchen and bathroom. The hybrid charges for that.
- A larger shared-space percentage makes sense here because the living room is big; with a small living room you would lower it and the couple’s share would fall.
Not so fair when
- If the couple will move out together and the roommate would struggle to fill the flat, some households ask the couple to cover a little more for that risk; that is a negotiation, not maths.
- If one partner is often away, the per-person part overcharges them; adjust bills by days home.
- Don’t forget the deposit: if the couple paid two-thirds of it, they get two-thirds back (see the deposit scenario).
This is general information about splitting costs between yourselves, not legal advice. Your lease and your state’s law decide what you owe the landlord.
Sources
- Spliddit, Assign Rooms and Share Rent. Checked 2026-10-05.
- Gal, Mash, Procaccia and Zick, Which Is the Fairest (Rent Division) of Them All? (J. ACM 64(6), 2017). Checked 2026-10-05.
- Francis Su, Harvey Mudd College, Fair Division Calculator (historical page). Checked 2026-10-05.
Related situations
A couple and a single: who pays what?
Per room is unfair to the single person; per person is unfair to the couple, who share one bedroom. The hybrid splits the shared space by heads and the bedrooms by size.
Open the example Split rentFour friends, three bedrooms, one shared room
Two people sharing the big room give up privacy, but they also get the most space. The hybrid split prices both: they pay per head for the shared rooms and half the big room each.
Open the example Split rentOne deposit cheque, three roommates
Landlords often return a shared deposit as one payment. Splitting it fairly means starting from what each person paid in, then taking out deductions the right way.
Open the example