To split expenses with roommates, sort every cost into rent, shared bills, shared supplies and things one person uses alone. Split rent evenly or by room size, split bills and shared supplies evenly, and keep personal costs out of the pool. Keep a running list of who paid what, settle once a month with as few transfers as you can, and agree on big shared purchases (a couch, a vacuum) before anyone buys them, including what happens to them when someone moves out.
This post walks through a full month for three roommates, then covers groceries, furniture bought for the flat, the deposit and what to do when someone leaves.
Sort costs into four groups
Many arguments between roommates start with a cost nobody agreed on. A short sort at the start avoids most of them.
- Rent: the biggest number and the one most worth getting right. Split it evenly if the rooms are alike, or by room size if one room is clearly bigger or has its own bathroom.
- Shared bills: electricity, gas, water, internet, sometimes trash pickup. These are usually split evenly. We covered them in detail, including move-ins mid-month and one person using more, in how to split utilities and internet with roommates.
- Shared supplies: toilet paper, dish soap, cleaning spray, trash bags, and any food the household agrees to share. Split evenly.
- Personal costs: your own food, your phone, your streaming accounts, your takeout. These stay yours, even when one card pays for a mixed shopping trip.
The fourth group matters more than it looks. When one person's protein bars end up in the shared pool every week, the others notice long before anyone says anything.
Rent: evenly or by room size
If the rooms are about the same, an even split is the fairest and the easiest. If they aren't, split by size. Say three roommates rent a flat for $3,000 a month. One bedroom is 200 square feet and the other two are 120 each, so the bedrooms add up to 440 square feet.
- the large room: 200 ÷ 440 of the rent, about $1,364
- each smaller room: 120 ÷ 440 of the rent, about $818
Those come to $3,000 once you round so the cents add up. Some households split only part of the rent by size (say half evenly, half by size) because the kitchen and living room are shared equally no matter whose room is bigger. Our rent split calculator does either version, and it can also split by income.
A worked month with three roommates
Here is one month, with the rent split by room size from above and everything else split evenly. Roommate A has the large room.
- Rent, $3,000: A pays the landlord the full amount.
- Electricity, gas and internet, $249: B holds the accounts and pays them.
- Shared groceries and staples, $180: A pays $120, C pays $60.
- Cleaning supplies and toilet paper, $45: C pays.
Rent shares are $1,364 for A and $818 each for B and C. Everything else adds up to $474, so each person's share of that is $158.
Now compare what each person paid with what they owe:
- A owes $1,364 + $158 = $1,522 and paid $3,120. A is owed $1,598.
- B owes $818 + $158 = $976 and paid $249. B owes $727.
- C owes $818 + $158 = $976 and paid $105. C owes $871.
Check: $727 + $871 = $1,598, so the balances net to zero. Settle with two transfers: B sends A $727 and C sends A $871.
Do the netting once a month on a fixed day. Settling every receipt as it happens means a dozen small payments, and some of them get forgotten.
Groceries: share less than you think
Fully shared groceries work for some households, usually ones that cook together most nights. For everyone else they cause trouble, because three people rarely eat the same amount or the same things.
A setup that works for most roommates:
- Share the staples everyone uses: milk, eggs, oil, rice, coffee, condiments, plus the household supplies above.
- Buy your own food for your own meals and keep it on your own shelf.
- When you cook for everyone, either split that shop evenly or take turns and call it even.
When one trip mixes shared and personal things, put only the shared part on the list. If you spent $90 and $35 of it was staples, add $35, not $90.
Things bought for the flat
A couch, a vacuum, a TV for the living room, a good frying pan. These last longer than the lease of the person who paid, so agree on two things before buying: who pays, and who keeps it.
There are two common ways to handle it.
One person buys it and keeps it
The buyer pays the whole price and takes it when they leave. Nobody else owes anything. This is the simplest choice for anything under a hundred dollars or so, and for things the buyer would want anyway.
Everyone buys it together
Say three roommates split a $600 couch, $200 each, and all own a third. Two years later one roommate moves out and the couch stays. Agree on what it's worth now (a used price you could sell it for), say $300. The leaving roommate's third is $100, so each of the two who stay pays them $50. If the couch is worn out and nobody would pay for it, it's worth $0 and nobody owes anything.
Write down which shared things exist, what each cost and who paid. A line in the group chat is enough, as long as it's findable two years later.
When a roommate moves out
Settle everything up to the move-out date first, so the person leaving walks away at zero. Prorate the bills that run past their last day: the utilities post above shows how to do it by days.
Then there's the deposit. The landlord usually holds it until the whole lease ends, so the person leaving early doesn't get their part back from the landlord. A common fix is for the incoming roommate to pay the leaving roommate their share directly. If the deposit was $3,000 and split the same way as rent, the person in a smaller room put in about $818, and the new roommate pays them that amount and takes their place on the deposit.
Before that hand-over, walk through the flat together and agree on any damage the leaving roommate caused. Whatever the landlord might keep for it can come out of the amount they receive.
Shared purchases come last: buy out the leaving roommate's part, or let them take what they paid for alone.
Your share is your spending
If you're the roommate who pays the landlord or the bills, your bank statement shows the full amounts. In the example, A's account shows $3,120 going out and $1,598 coming back in. A's real spending for the month is $1,522, and the $1,598 isn't income. It's two roommates paying their part of costs A fronted.
The same holds the other way: B's card shows $249 of bills, but B's utilities spending is $83, a third of $249. The $727 B sends A covers B's rent and the rest of B's shares. We wrote more about this in Splitwise and your budget.
If you track shared costs in Splitwise, Monio connects to Splitwise, links each bill to its card charge and counts only your share, so fronting shared costs doesn't make your month look bigger than it was.
Questions
How do you split expenses with roommates?
Sort costs into rent, shared bills, shared supplies and personal costs. Split rent evenly or by room size, split bills and supplies evenly, keep personal costs out of the pool, and settle once a month with as few transfers as you can.
How do roommates split groceries?
Most roommates share only the staples everyone uses, such as milk, oil, coffee and toilet paper, and buy their own food for their own meals. When one shopping trip mixes both, only the shared part goes on the list.
How do you split furniture with roommates when someone moves out?
Agree on what the piece is worth now, then the roommates who keep it buy out the leaving roommate's part. If three people split a $600 couch and it's worth $300 two years later, the leaving roommate's third is $100, so each of the two who stay pays $50.
What happens to the security deposit when a roommate moves out?
The landlord usually holds the deposit until the lease ends, so a common fix is for the incoming roommate to pay the leaving roommate their share directly. Agree on any damage the leaving roommate caused before that hand-over.