How to split rent and bills fairly with flatmates
In short
When rooms differ, split the rent in two parts: treat an agreed share of it, such as 40%, as paying for common space and divide that equally, then divide the rest by bedroom size, adjusting for extras like an attached bathroom. Split utilities and internet equally unless someone's use is clearly higher, keep groceries to a small shared staples list, and settle up on a fixed day every month so small debts never pile up.
On this page
Most flatmate money fights aren't really about money. They're about a 6,000 electricity bill nobody agreed how to split, or the person in the biggest room paying the same as the person in the box room, or a debt from March that nobody wants to bring up. Each of those has a simple fix, and it works best if you agree it before you need it.
How do you split rent fairly when rooms are different sizes?
Splitting rent equally only feels fair when the rooms are roughly the same. When they aren't, use a hybrid split:
- Pick a common-space share. Everyone uses the kitchen, living room, hallways and bathrooms equally, so part of the rent pays for those. Somewhere between 30% and 50% is a reasonable starting point. The more common space you have, or the smaller the bedrooms, the higher the share should be.
- Split the common-space share equally.
- Split the rest by bedroom size. Measure each room. Square metres or square feet both work, because only the ratio matters.
- Adjust for extras. Agree a fixed amount for things size doesn't capture, then move it between people.
Worked example: three rooms, rent of 30,000
The flat has three bedrooms of 15, 12 and 9 square metres (36 in total). The flatmates agree to treat 40% of the rent as common space.
- Common space: 40% of 30,000 = 12,000, split three ways = 4,000 each.
- Bedrooms: the other 18,000 is split by size. 15 ÷ 36 of 18,000 = 7,500. 12 ÷ 36 = 6,000. 9 ÷ 36 = 4,500.
Compared with an equal split of 10,000 each, the person in the large room pays 1,500 more and the person in the small room pays 1,500 less.
How 30,000 of rent splits across three rooms
- Common space (split equally)
- Bedroom size
Adjusting for extras. Say the medium room has an attached bathroom and everyone agrees it's worth 1,000 a month. The medium room pays 1,000 more, and the other two each pay 500 less: 11,000, 11,000 and 8,000. Agree the size of any adjustment before anyone chooses a room. Once people have picked, every adjustment looks like a negotiation.
Try it with your own numbers. Enter the total rent and each room's size, then move the slider for the common-space share:
Fair rent split calculator
| Person | Pays | vs equal split |
|---|---|---|
| Room 1 | 11,615 | +1,615 |
| Room 2 | 10,000 | 0 |
| Room 3 | 8,385 | −1,615 |
An equal split would be 10,000 each. Amounts are rounded to whole numbers.
What if you can't agree on what the rooms are worth?
Size is a good proxy, but people value different things: light, noise, a window that opens, distance from the kitchen. If you're stuck, let everyone say what each room is worth to them and use those values. Researchers at Carnegie Mellon built a tool for exactly this, Spliddit: each person says what each room is worth to them, and an algorithm recommends who takes which room and what each person pays, with the aim that nobody envies anyone else's deal.
A low-tech version: write the hybrid prices on paper, and if two people want the same room, the one willing to pay a bit more for it gets it, with the extra knocked off the other rooms.
How should flatmates split utilities, internet and groceries?
Utilities and internet: equal by default
Electricity, water, gas and internet are usually split equally per person. It's simple and everyone can check it. Make exceptions only when there's a clear, lasting difference:
- Someone runs an air conditioner or heater in their room most of the day. Agree a fixed monthly top-up rather than trying to meter it.
- Someone works from home full time. Same approach: a small agreed top-up, or decide the peace of equal splitting is worth more.
- A couple shares one room. Split utilities per person, not per room, and usually the common-space share of the rent too: two people use the kitchen and bathroom.
Subscriptions are opt-in. If only three of four flatmates want a streaming service, those three split it.
Groceries: shared staples, personal everything else
Fully shared food budgets rarely survive different diets, schedules and appetites. What works in most houses:
- A short staples list everyone uses: cooking oil, salt, spices, tea, coffee, milk, toilet roll, washing-up liquid, cleaning supplies. Split equally.
- Personal food is personal. Buy your own and label it if you need to.
- Cooking together is a separate event. Whoever buys the ingredients logs the cost, and it's split among whoever ate.
Rotate who restocks the staples, or keep a small kitty everyone tops up monthly. Either works if it's written down.
House money rules to agree before problems start
Agree these in your first week, or right now if you've already moved in. Share them in the house chat so everyone has the same version. Copy this list, edit the specifics, and get everyone to agree:
House money rules
0 of 11 done
The last rule matters most. A flatmate who says "I'll be short this month, can I pay on the 10th?" is a minor inconvenience. One who goes quiet is a crisis.
How to settle up without chasing anyone
Pick one settle-up day each month, ideally a few days after most people are paid. On that day:
- Everyone checks the shared expenses for the month.
- Work out net balances. If A owes B 800 and B owes A 300, A just pays B 500.
- Everyone pays what they owe within 48 hours.
- Mark it settled, so the next month starts at zero.
Small, regular settlements keep things friendly. A few hundred owed this month is nothing. Five months of unsettled small amounts become a figure nobody wants to look at.
Tip: Doing this in Numora
Make a group for the flat and invite everyone by link. Add rent as a recurring monthly expense so you get a reminder when it's due, use Split manually to enter each person's amount, and tap Mark Paid once it's paid (recurring expenses aren't added automatically). Log shared bills and groceries as they happen. The Dues tab shows simplified balances of who owes whom. Whoever is owed can tap Notify to send a reminder, so nobody has to chase in person. Settle records a payment once it's made; the money itself moves however you normally pay each other.
What happens when someone moves out mid-month?
Prorate by days. Divide the person's monthly share by the number of days in the month and multiply by the days they lived there.
Example: the person in the medium room pays 10,000 a month and moves out on the 12th of a 30-day month.
- Days they lived there: 12 of 30.
- Their rent for the month: 10,000 × 12 ÷ 30 = 4,000.
- The remaining 6,000 is covered by the incoming flatmate if there is one.
If there's no replacement, the answer depends on what you agreed and on the lease. On most joint leases, the remaining flatmates still owe the full rent to the landlord. That's why "help find a replacement" belongs in the house rules.
Also sort out:
- Utilities. Read the meters on move-out day if you can, or split the bill for that period by days lived.
- Deposit. Tell the landlord or agent about the change and have the new flatmate pay their deposit share through them, not straight to the person leaving, so the deposit record and the agreement show who now holds which share. Shelter England warns it's harder to prove you paid if you hand it to the tenant who's leaving. Deposit rules differ by country, so check yours.
- Shared items. For things bought together, like a sofa or a fridge, agree a fair second-hand value. The people staying buy out the leaver's share, or the leaver takes the item and buys the others out.
- Final settle-up. Do a full settle-up before they leave. Collecting money from someone who's moved across the city is much harder.
How do you handle a flatmate who doesn't pay?
First, know where you stand
If you're all on one joint tenancy, the landlord can usually ask any of you for the full rent. Shelter England puts it plainly: in a joint tenancy, everyone on the agreement is responsible for the whole rent, and the landlord could try to evict everyone over unpaid rent. If you each have a separate agreement, you're generally only responsible for your own share. Rules differ by country and by lease, so check yours.
That's why a missed payment needs dealing with quickly, even when it feels awkward.
Step 1: a friendly nudge (day 1 to 3)
Assume it's an oversight. Message them directly, not in the group chat:
"Hey, just a heads-up that your share of the rent (10,000) hasn't come through yet. It's due to the landlord on the 5th. Can you send it today or tomorrow?"
Step 2: a direct conversation (about a week late)
Talk in person, privately. Be specific and leave room for them to explain:
"I wanted to talk about the rent. Your share for this month still hasn't come in, and the rest of us had to cover it so we didn't fall into arrears. Is something going on? If money's tight, I'd rather we work out a plan than have it hang over the house."
Step 3: agree a plan in writing
If they genuinely can't pay, agree a repayment plan and confirm it by message so there's a record:
"Just confirming what we agreed: you'll pay 5,000 on the 15th and 5,000 on the 30th, on top of next month's rent as normal. Thanks for being upfront about it."
Step 4: if it's still not resolved
- Cover the gap if you can, so the household doesn't fall into arrears with the landlord, then recover it from the flatmate. That's the approach Shelter Scotland suggests.
- Talk to the landlord early and explain the situation, rather than letting them discover a short payment.
- Put it in writing. Send a letter or email saying what's owed and why, with evidence such as bank transfers and messages, and keep a copy. Shelter Scotland notes you'll need it to show you tried to resolve things before going to court.
- Small claims are the last resort. Most places have a simple court process for small debts. It's slow and stressful, and it rarely helps if the person has already left with no forwarding address.
Many cases are sorted at step 2. Clear rules, a fixed settle-up day and a written record make that far more likely.
If you're a couple sharing a room in a bigger house, you'll also need to decide how the two of you split your share. The couples and money guide covers that. And if settling up keeps slipping, a short weekly money review helps; there's a 10-minute version in money habits that stick.
Key takeaways
- Split rent in two parts: an equal share for common space, and the rest by bedroom size.
- Adjust for real differences such as an attached bathroom, a balcony or a much better room, and agree the adjustment before anyone picks a room.
- Split utilities and internet equally by default; keep shared groceries to a short staples list.
- Settle up on a fixed day every month, not whenever someone remembers.
- On a joint tenancy, the landlord can usually ask any of you for the whole rent, so deal with a missed payment quickly.
Frequently asked questions
Whose name should the bills go in?
Ideally spread them: one person holds the electricity, another the internet, and so on, so nobody carries all the risk. Whoever holds a bill should share the statement with everyone when it arrives, so the split is checked against the real amount.
Can we split rent by income instead of by room?
You can if everyone agrees, but it's rare between flatmates. Income-based splits suit people who share finances long term, like couples. Between flatmates, paying for the space you get is usually seen as fairer and is easier to keep when someone moves out.
References
- Shelter England, Problems with rent in shared housing england.shelter.org.uk
- Shelter England, Joint tenancies: paying a deposit (updated 1 May 2026) england.shelter.org.uk
- Shelter Scotland, Problems with people you live with scotland.shelter.org.uk
- Carnegie Mellon University (2014), A Better Way to Slice the Pie: Spliddit fair division cmu.edu