Your apartment
Rent Split Calculator
Split rent fairly between roommates. Equal, by room size, by income, or custom percentages.
Monthly rent
Split method
Roommates
Add each person and the info needed for your chosen method.
Each person pays
Total
$0.00
Enter rent and add a roommate to see the split.
How it works
Four ways to split rent. All mathematically fair.
There's no single "fair" way to split rent between roommates. What's fair depends on your rooms, your incomes, and the conversation you've had. This calculator handles the four methods that actually work.
Equal works when rooms and incomes are similar. Simplest, least friction. By room size is the default when bedrooms are genuinely different, with adjustable premiums for en-suite bathrooms, walk-in closets, balconies, and penalties for street noise or bad light. By income is fairer when paychecks differ meaningfully (rule of thumb: more than 25%). And custom % just applies whatever ratio you've already worked out.
All methods round cleanly so every share adds up to the exact total rent. No pennies missing, no one paying an extra 3 cents.
Room-size premiums
Add adjustments for en-suite bathrooms, walk-in closets, private balconies, or street noise. Each premium adjusts the room's effective size.
Proportional by income
Each person's share matches their share of household take-home pay. Automatic fairness when one partner earns significantly more.
Custom percentages
Already negotiated a split? Enter the percentages directly and see dollar amounts instantly.
Private by default
Runs entirely in your browser. Your roommates, rent, and income are never sent anywhere. Saved to local storage.
Frequently asked questions
How do you split rent fairly between roommates?
Four common methods work. Equal split when rooms and incomes are similar. By room size (with premiums for en-suite, closet, balcony) when bedrooms are genuinely different. By income proportionally when paychecks differ by more than 25%. Custom percentages if you've already negotiated a split. This calculator supports all four.
Should a roommate with an en-suite bathroom pay more?
Usually yes. Treat an en-suite as adding roughly 15% to the room's effective size. Walk-in closet adds 8-10%. Private balcony adds 10%. These are judgment calls, but the calculator lets you toggle premiums per room so the math reflects the real value each person gets.
How is rent split by income calculated?
Each roommate pays a share of rent proportional to their share of the combined household income. If you earn $3,200 and your roommate earns $6,800 (total $10,000), you pay 32% and they pay 68%. Use take-home (net) income, not gross, since that's what actually hits your account.
When should we use proportional-by-income instead of equal?
Rule of thumb: if incomes differ by more than 25%, or if equal rent would eat more than 35% of one person's take-home, proportional is usually fairer. Below that, equal is simpler and typically fine.
Does this calculator save my work?
Yes. Everything is saved in your browser's local storage. Close the tab, come back later, your roommates and settings are still there. Nothing is sent to a server.
Can I use this for flatshares in Europe or any country?
Yes. The calculator supports any currency (EUR, GBP, PLN, SEK, etc.). It uses percentages for splitting, so the result is always mathematically consistent regardless of currency or country.
supasplitRent is month one. The rest is a hundred small bills.
Supasplit tracks rent, utilities, groceries, and shared subscriptions across every roommate. Set the ratio once, let reminders do the awkward bits. Free for small apartments, $3.99/mo for unlimited.