How to split bills with roommates fairly
A practical guide to splitting rent, utilities, internet and groceries with roommates, with fair formulas for room size and usage, and a simple monthly system.
Living with roommates is cheaper than living alone, right up until the electricity bill becomes a weekly argument. The households that get along best are not the ones with the cheapest bills. They are the ones with clear rules and one record everybody trusts.
Start with a roommate agreement
Before anyone moves in, agree on these five points and write them down:
- Which bills are shared: rent, electricity, gas, water, internet, streaming, cleaning supplies.
- How each one is split: evenly, by room size or by usage.
- Whose name is on each account, and therefore who pays it.
- When everyone pays back: within a week of each bill, or once a month.
- What happens when someone moves in or out.
It feels formal, but it takes ten minutes and prevents most roommate fights about money.
How to split rent
Evenly works when the rooms are similar. Rent of 2,400 shared by three people is 800 each.
By room size is fairer when one room is clearly bigger, has its own bathroom or a balcony. Weight the rent by the floor area of each private room:
| Room | Size | Share | Rent |
|---|---|---|---|
| Room A | 150 sq ft | 41.7% | 1,000 |
| Room B | 120 sq ft | 33.3% | 800 |
| Room C | 90 sq ft | 25% | 600 |
| Total | 360 sq ft | 100% | 2,400 |
Some households also add a small premium for an ensuite bathroom or parking space. Agree on it before anyone picks a room.
How to split utilities
For electricity, gas and water, an even split is usually the fairest option that nobody has to police. Switch to a different split only when usage is clearly uneven:
- One roommate works from home every day and runs the heating.
- One roommate has a partner who practically lives there.
- One room has a space heater or an air conditioner running all day.
In those cases, agree on a bigger share for that person, for example 40% instead of 33%, rather than trying to measure every kilowatt.
How to split the internet bill
Internet providers such as Xfinity, Spectrum or BT generally send one bill to one account holder, and there is usually no option to split it between roommates. The simple fix:
- One roommate holds the account and pays the bill.
- Everyone else pays back an equal share each month.
- The payment goes into your shared record, so the account holder never has to chase anyone.
If one person streams 4K all day and another is rarely home, an equal split is still normal. Internet plans have a fixed price, so heavy use does not add to the bill.
Groceries and household supplies
Shared basics like toilet paper, cleaning products, oil and spices are easiest with a kitty: everyone puts in the same amount each month, and whoever does the shopping pays from it. Personal food stays personal.
Half Tab has a kitty built in. Record that everyone chipped in to the person holding the pot, log the shopping as paid by them, and the balances stay right without any extra maths.
When someone moves in or out mid-month
Prorate every shared bill by the number of days each person lived there.
Example: the utility bill for a 30-day month is 90, or 3 a day. A new roommate who moved in on day 19 lived there 12 days and owes 36. The rest is split between the roommates who were there the whole month.
A simple monthly system that works
- Each bill is paid by whoever holds the account.
- Every bill is added to one shared group as soon as it arrives.
- Once a month, everyone settles up in the fewest payments possible.
That last step matters. With three roommates and six bills, a naive approach means up to a dozen small transfers. A bill splitting app nets everything out, so most months it is one or two payments.
Make it easy with Half Tab
Create a group for your home in Half Tab, add each roommate, and log bills as they arrive: rent by room size with shares, utilities equally, and the internet bill by whoever pays it. Everyone sees the same balances, and when you settle up the app shows exactly who pays whom. It even works with no internet, which is handy when the internet bill is the thing that has not been paid.
For couples living together, see how to split bills as a couple. For a fairer split when incomes differ, see splitting bills based on income.
Frequently asked questions
How do you split utilities with roommates?
Most households split electricity, gas and water evenly, because usage is hard to measure per person. If one roommate clearly uses more, for example by working from home all day or running a space heater, agree on a bigger share for them up front.
How do you split rent when rooms are different sizes?
Weight the rent by room size. Add up the floor area of the private rooms, then each roommate pays their room's share of that total. Shared spaces like the kitchen are covered automatically, because everyone uses them.
How do roommates split an internet bill like Xfinity?
Internet providers such as Xfinity usually bill one account holder. That person pays the bill each month and the others pay back their share, normally an equal split. Record it in a shared tracker so the account holder is never left chasing payments.
What happens when a roommate moves out mid-month?
Prorate by days. Divide the monthly bill by the number of days in the month, then multiply by the days each person lived there. A 90 utility bill over 30 days is 3 a day, so someone who stayed 12 days owes 36.
