Should a roommate's partner pay rent or utilities?
Quick answer
It depends on how many nights a week the partner stays. A workable rule is nothing owed up to 2 nights, a share of utilities and groceries at 3 to 4 nights, and a talk with everyone about rent at 5 or more. Divide the bill by person-nights: $318 over 106 person-nights is $3.00 a night.
Key points
- A starting rule: 0 to 2 nights a week is a guest, 3 to 4 nights shares the bills that rise with use, and 5 or more is a conversation about rent.
- Per-night cost is the bill divided by person-nights. On $318 and 106 person-nights, a night costs $3.00.
- A partner who stays 16 nights in a month takes $48 of that bill. The other roommates pay $90 each instead of $106.
- The roommate whose partner it is raises the topic first, and covers the partner's share if the partner will not.
On this page
What is a fair rule for a roommate’s partner?
The fair rule is the one everyone agreed to before it was a problem, and nights a week is the easiest thing to agree on. A roommate’s boyfriend or girlfriend is the usual case, and the same lines work for any partner. They are a starting point, not a standard. Move them if your household wants to.
| Nights a week | How to treat them | What they chip in |
|---|---|---|
| 0 to 2 | A guest | Nothing |
| 3 to 4 | A regular | A share of utilities and groceries they use |
| 5 to 7 | Treat as a resident | Everyone talks, including rent |
Under 3 nights, the extra water and power are small, and tracking them can cost more goodwill than money. From 3 nights, the use adds up. At 5 or more nights, treat the person as living there for money purposes, even if their name is on nothing, and say so out loud.
How do you work out the cost per night?
Divide the bill by person-nights. A person-night is one person sleeping there for one night, so a month with three roommates is 90 person-nights before anyone else stays.
Say three roommates share an apartment for a 30-day month, and electric, water and gas come to $318. One roommate’s partner stays 16 nights.
- Count the person-nights. Three roommates at 30 nights is 90. Add the partner’s 16, and the total is 106.
- Divide the bill. $318 / 106 = $3.00 a person-night.
- Multiply by each person’s nights. Each roommate is 30 x $3.00 = $90. The partner is 16 x $3.00 = $48.
| Person | Nights | Share at $3.00 |
|---|---|---|
| Roommate 1 | 30 | $90 |
| Roommate 2 | 30 | $90 |
| Roommate 3 | 30 | $90 |
| Roommate 3’s partner | 16 | $48 |
| Total | 106 | $318 |
Without counting the partner, the bill splits three ways at $106 each. With the partner counted, the other two roommates save $16 each. The roommate whose partner stays pays $90 plus the partner’s $48, which is $138 in all, $32 more than the plain split. These numbers are an illustration, not averages.
What about internet, groceries and rent?
Internet is usually a flat charge, so a partner does not raise it. Whether the partner joins that split is a judgment call. If they do, a $60 internet bill goes from $20 a person among three roommates to $15 a person among four, a $5 saving for each roommate. A simple rule is to leave the partner out of internet until the 5-night line.
Groceries follow what people eat. Count the partner’s meals, or have them buy their own food on the nights they stay. How to split groceries with roommates covers the methods.
If rent is set per room, a partner staying a few nights does not change what the room costs. At 5 or more nights, the household can choose to adjust the room’s rent. How to split rent with a couple has the options. This page covers money only. Who may live in the unit depends on your lease and local rules.
Who raises it, and how?
The roommate whose partner it is should raise it, and early. It is their guest, and it is easier to hear from them than from someone doing the math on a Sunday night. A short message does it:
“Sam has been here about four nights a week. Do you want to add him to the utilities split, or should I cover his part?”
If you are the other roommate, make it about a rule instead of a person: “Can we agree how overnight guests work with the bills? Something like a share from the third night a week.”
Put the result in writing. What to include in a roommate agreement lists the guest line to add.
How do you track it in EvenOut?
Make a “Household” group and add the partner as a guest, using “Add a guest”. EvenOut tracks a guest’s share now and lets you invite them later. Add the bill as an expense, open “How to split”, choose “Shares” and type each person’s nights: 30, 30, 30 and 16. The pill reads 106 shares with the dollar value of one share, and each person’s amount shows under their name. Count nights at the end of the month from a shared note.
EvenOut records who owes what. It does not collect the money, so the partner, or the roommate covering them, pays whoever paid the bill.
What should you do next?
Pick the nights-a-week lines, agree what counts as a night, and tell your roommate before the first bill. If you are deciding what else the household splits, what expenses roommates should split is the next read. For the rules that apply to a month’s bills, see how to split utilities between roommates.
Frequently asked questions
What if the partner stays 3 nights some weeks and 6 nights in others?
Count the nights over the whole month and use that total, not the weekly bracket. The brackets are for deciding when to start the conversation. The bill is split on what actually happened, so a month with 11 nights costs the partner 11 nights at the per-night rate.
What if my roommate will not ask their partner to pay?
Then the roommate carries the partner's share themselves. In the example on this page that is $48 added to their own $90, so they pay $138 and the other two pay $90 each. The other roommates should not be left covering a cost they did not agree to.
How do we count nights without it turning into an argument?
Agree what counts as a night before you start, such as sleeping there, and note each night on a shared calendar. Count at month end. Counting by the whole group on one date removes the chance that one person is guessing from memory.
Keep reading
- Guide How to split rent when roommates include a couple Count a couple per head, per room or in between. On $2,400 the couple pays $1,600, $1,200 or $1,440. Plus utilities and a partner moving in.
- Guide How to split utilities between roommates One $240 month run through four rules: equal, by people, by days present and with a heavy user extra charge. Plus who holds accounts and when to repay.
- Guide What to include in a roommate agreement Twelve money clauses for a roommate agreement, each with fill-in wording: rent shares, utilities, guest costs, late payment, notice and move-out money.
- Guide What expenses roommates should split, and which to skip A table of 12 roommate expenses with a default split and one rule each, plus a three question test for new purchases and a spending limit.
- Guide How to split groceries with roommates Five ways to split groceries with roommates, with the money worked out, including a $186.40 receipt where personal items come off the top first.