Splitting rent evenly is the default, but it is not always fair.
If every bedroom in the apartment is roughly the same size and every roommate has the same access to shared spaces, an equal split works fine. The moment one bedroom is noticeably larger, has a private bathroom, has a walk-in closet, or is the only room with real windows, the equal split quietly becomes a tax on whoever ended up in the smaller room.
The fix is to decide the split before anyone signs the lease and to write it down somewhere both roommates can find later.
Three common ways to split rent
Equal split
Everyone pays the same amount. Best for identical rooms, close friends who genuinely do not care, or short-term arrangements.
By private square footage
Add up the square footage of each private bedroom. Divide each person's room by that private total to get their percentage. Multiply the rent by that percentage. Shared spaces (kitchen, living room, hallways, shared bathrooms) stay out of the math — everyone uses them, so no one pays extra for them.
By income
Add every roommate's monthly take-home pay. Divide each person's income by the total, then apply that percentage to rent. Common with couples and with roommates who explicitly agree to it. Only works if everyone opts in.
Worked example: three roommates, unequal rooms
Say three roommates share a $2,700 apartment.
- Room A (master, private bathroom): 180 sq ft
- Room B (medium): 130 sq ft
- Room C (small, no closet): 90 sq ft
Private-room total: 400 sq ft. Each roommate's percentage is their room divided by 400.
- Room A: 45% × $2,700 = $1,215
- Room B: 32.5% × $2,700 = $877.50
- Room C: 22.5% × $2,700 = $607.50
That is meaningfully different from a $900 equal split — the person in the small room saves almost $300 a month, and the person in the master pays for the private bathroom they actually enjoy.
Utilities and shared subscriptions
Pick one system per bill and stick to it. Two options that work:
Split each bill the same way you split rent. Simple. Predictable. Works even when the amounts change.
Run a shared tab. Whoever's name is on a bill pays it, logs it in a shared note or spreadsheet, and the group settles up once a month. Best if you have three or more roommates and multiple bills in different names.
Common bills to include: electricity, gas, water, trash (if not in rent), internet, streaming subscriptions that everyone uses, household supplies (paper towels, cleaning stuff, hand soap). Keep personal subscriptions and personal groceries separate.
The security deposit
Each roommate should pay their own share of the deposit up front, in the same proportion they pay rent. Write down who paid what and when. When someone moves out, the landlord returns the deposit to the lease-holder — who then owes each departing roommate their original share back, minus any documented damage that person caused.
This one detail avoids most roommate money fights. Undocumented deposits are the leading cause of "why is my ex-roommate texting me?" nine months later.
Common mistakes
- Splitting equally without checking room sizes first.
- Letting one person "just handle" a utility as a favor.
- Not writing down who paid the deposit or how much each person contributed.
- Rolling personal subscriptions into the shared bill pile.
- Waiting until move-out to have the utilities conversation.
Quick reference
- Similar rooms → equal split.
- Different rooms → private square footage.
- Very different incomes and everyone opts in → by income.
- Utilities → same method as rent, or a shared monthly tab.
- Deposit → proportional to rent share, documented in writing.
Frequently asked questions
Is it fair to split rent equally when bedrooms are different sizes?
It can be, if everyone agrees up front. But if one bedroom is noticeably larger, has a private bathroom, or is the only one with a closet, splitting by square footage is usually fairer. Measure each private room, add the private space totals, and give each roommate their percentage of the private total. Shared spaces (kitchen, living room, bathrooms used by everyone) stay out of the calculation.
How do you split utilities that vary month to month?
Either split each bill the same way you split rent (equal or by room size) and reconcile monthly, or run a shared tab and settle up once a month. Never let one person 'just cover it' as a favor — small imbalances build resentment fast. If usage is genuinely uneven (someone runs the AC constantly, or works from home), agree on a fixed adjustment rather than trying to prove it every month.
Who pays the security deposit?
Each roommate pays their own share up front, matched to the same percentage they pay for rent. Write it down. When someone moves out, the landlord returns the deposit to the lease-holder, who owes each departing roommate their share back minus any documented damage they caused.
Should we split streaming subscriptions?
Only if everyone actually uses them. Netflix, Spotify Family, and HBO are usually worth splitting because sharing is the whole point. Cloud storage, gym apps, and single-person subscriptions are not — those stay with the person who wants them.
What if one roommate makes way more money?
Some households split by income (each person pays a percentage of rent proportional to their share of total household income). This is common with couples and among roommates who explicitly want that arrangement. It only works if everyone opts in — do not surprise a lower-earning roommate with a higher-percentage rule after signing the lease.
Running a shared roommate expense tab? BillSplitterApp works for anything with items and a total, not just restaurant checks.