The short answer
If your rooms are about the same, split the rent equally. If they are not, split it by room size. If your incomes are very different and everyone is comfortable with that, splitting by income is a third option. Whichever you choose, agree it before you sign the lease and write it down.
You can try all three with your own numbers in the rent split calculator.
Method 1: split it equally
Divide the total rent by the number of people. Three roommates paying $2,400 each pay $800.
Good for: similar rooms, friends who want something simple.
Watch out for: one person having a clearly better room. The equal split hides a real difference in value, and resentment tends to surface later.
Method 2: split by room size
Each person pays a share of the rent equal to their room’s share of the total private space. Leave out the kitchen, living room and hallways, because everyone uses those equally.
Worked example. The rent is $2,400 and the rooms are 180, 140 and 100 square feet, 420 in total.
- 180 ÷ 420 = 42.86%, so that person pays $1,028.57
- 140 ÷ 420 = 33.33%, so that person pays $800.00
- 100 ÷ 420 = 23.81%, so that person pays $571.43
The three amounts add up to exactly $2,400.00. When a share does not divide into whole cents, one person absorbs the extra cent so the total is exact.
Room size is not the only thing that matters. Some households add or subtract a fixed amount for a private bathroom, a walk-in closet, a window that faces a wall, or a room next to a noisy street. Agree these adjustments openly and apply them before you divide the rest.
Method 3: split by income
Each person pays a share equal to their share of the household’s combined income.
Worked example. The rent is $2,400 and monthly incomes are $6,000, $4,000 and $2,000, $12,000 in total.
- $6,000 ÷ $12,000 = 50%, so that person pays $1,200
- $4,000 ÷ $12,000 = 33.3%, so that person pays $800
- $2,000 ÷ $12,000 = 16.7%, so that person pays $400
Good for: couples and friends with very different pay, where an equal split would take a much bigger bite out of one budget.
Watch out for: the shares change whenever someone’s income does, and everyone has to be comfortable disclosing what they earn.
What to split beyond rent
Utilities and internet
Electricity, gas, water and internet are usually split equally. Everyone uses them, and tracking individual usage is rarely worth the effort. One person often puts the bills in their name and the others pay them back, so agree who does that and by which day of the month.
Groceries and household supplies
Shared staples such as cleaning products, toilet paper and cooking basics work well as shared expenses. Personal food usually does not. Decide what counts as shared, and log each purchase when it happens so nothing is forgotten. See how the roommate expense tracker handles this.
Deposits and one-off costs
Split the security deposit the same way as the rent, and write down how it will be returned when someone moves out. Furniture and appliances bought together need a rule too: who keeps them when the household breaks up.
Put it in writing
A short shared note is enough. Include the rent split and each person’s amount, the due date and who collects, how utilities are divided, what happens if someone is away or moves out, and how you will revisit the arrangement. Revisit it whenever a room changes, someone joins or leaves, or someone’s situation changes.
Keep track so it stays fair
Most roommate arguments are not about the rent itself. They are about who paid for what and whether it was ever repaid. Keeping a running record of who paid and who owes removes the guesswork. That is what Squadly is for: log an expense once, choose how to split it, and everyone’s balance updates. It is free while in early access.