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.
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 | 150 × 1 | $640.00 | $800.00 | $1,440.00 |
| Single | 1 | 120 × 1 | $320.00 | $640.00 | $960.00 |
| Total | 3 | $960.00 | $1,440.00 | $2,400.00 |
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 a friend rent a two-bedroom for $2,400. The couple takes the 150 sq ft room; the friend takes the 120 sq ft room. Three people use the kitchen, living room and bathroom, so 40% of the rent is split by person (three heads) and 60% by bedroom floor area.
- Couple pays $1,440.00, $720.00 each: 1.11× average floor area, 2 people share the common space.
- Single pays $960.00: 0.89× average floor area.
- Total: $2,400.00, 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
- Three people really do use the shared rooms: the couple puts twice the wear on the kitchen and bathroom and twice the demand on hot water.
- The couple’s bedroom is still one bedroom, so they don’t pay two bedrooms’ worth of private space.
- Everyone can see the two parts of each amount (the per-person part and the room part), so the result is explainable in one sentence.
Not so fair when
- If one partner is rarely there (they keep their own place), splitting the common space by three heads overcharges the couple; count them as 1.5 or use the days-home split for bills.
- If the couple’s room is much larger because they need it for two people, some households agree to discount the room part a little. Decide that before signing, not after.
- Utilities follow use more closely than rent does. Keep the rent split and the bills split separate rather than forcing one formula onto both.
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 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.
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 rentSplit rent in proportion to income
Each person pays the same share of their income, so a big pay gap doesn’t turn into a big gap in what is left over each month.
Open the example