How do you split rent fairly between roommates?

There are three common answers and the page does all of them. Equally, when the rooms and incomes are similar. By room, weighting a bigger or en-suite room above a smaller one, when the rooms differ. By income, so each person pays the same share of their earnings, when the incomes differ a lot — common for couples. Fair is whichever rule everyone accepts in advance.

How do you split rent based on income?

Add everyone's monthly income, work out each person's percentage of that total, and apply the percentage to the rent and bills. Two people on {{$5000}} and {{$3000}} share {{$2000}} of rent as 62.5% and 37.5%: {{$1250}} and {{$750}}. Choose 'In proportion to income' and enter each income.

How should rent be split for a couple sharing with a single roommate?

Usually by room, since the couple's room is one room: a common approach is to weight the couple's room 1.5 or so against 1 for the single room, so the couple pays 60% and the roommate 40% of the rent. Bills, which scale with people, are often split per head instead — three ways with the couple paying two shares.

Should bills be split the same way as rent?

Rent tends to follow the room and bills tend to follow the people, so many households use a room split for rent and an equal split for bills. The page applies one rule to both; run it twice to combine the two.

Rent Split Calculator (Equal, by Income or by Room Size)

Divide rent and bills between roommates equally, in proportion to income, or by room weight.

Inputs

Monthly rent

110,000,000

Shared utilities and bills

0100,000

Split

Who lives there

Name
Monthly income
Room weight

Income is only used for the income split, the weight only for the room split — 1 is a standard room, 1.5 a big one with its own bathroom, 0.7 a box room.

Include CalculateEveryday mark

Each of 3 pays

900.00

Split by equal split

Who	Share	Rent	Utilities	Pays
Person 1	33.3%	800.00	100.00	900.00
Person 2	33.3%	800.00	100.00	900.00
Person 3	33.3%	800.00	100.00	900.00

Monthly total

Person 1900(33%)
Person 2900(33%)
Person 3900(33%)

Rent + utilities: 2,400.00 + 300.00 = 2,700.00 a month
Working: 2,700.00 ÷ 3 = 900.00 each
People: 3

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What each Rent Split input means

Monthly rent: The monthly rent for the whole home.
Shared utilities and bills: Shared monthly bills — power, gas, water, internet. They are split by the same rule as the rent; leave this at 0 to split the rent alone.
Split: Equally, in proportion to each person's income, or by a weight for each room.
Who lives there: One row per person paying, yourself included, with their monthly income (for the income split) and their room's weight (for the room split): 1 for a standard room, more for a bigger or en-suite room, less for a box room.

Rent Split formula

Equal: each pays (rent + bills) ÷ people · By income: each pays (rent + bills) × own income ÷ combined income · By room: each pays (rent + bills) × own weight ÷ combined weight

\text{pays}_i = (R + U) \times \frac{w_i}{\sum w}

Add the rent and the shared bills, then decide what each person's share is. The equal split divides by the number of people. The income split gives each person the same fraction of the total as their income is of the combined income, so someone earning twice as much pays twice as much — the 'fair by ability to pay' rule couples and shared houses often use. The room split does the same with a weight per room: a standard room is 1, a large room with its own bathroom might be 1.5, a box room 0.7, and each person pays their weight's share of the whole. The table shows every person's percentage, rent portion, bills portion and monthly total, and the income and room splits also show what an equal split would have been, so the difference is visible before anyone agrees to it.

Rent Split worked example

$2,400 rent plus $300 of bills is $2,700 a month. Split equally three ways, each roommate pays $2,700 ÷ 3 = $900. Split by income, with the three earning $4,000, $3,000 and $2,000 a month (a combined $9,000), the shares are 4⁄9, 3⁄9 and 2⁄9: $1,200, $900 and $600. The middle earner pays the same either way; the highest earner pays $300 more and the lowest $300 less.

Where the Rent Split calculator can give the wrong answer

Enter every person who pays, including yourself — the head count is the number of rows, so three rows means three people, not 'two others plus me'.
The income split uses whatever you type as income; before-tax and after-tax figures give different shares, so agree which one the household uses.
Room weights are a judgement, not a formula. The page applies whatever weights you give; it cannot tell you whether the en-suite is worth 1.5 or 1.3 times a standard room.
Bills are split on the same basis as the rent. If the household wants rent by room size but bills equally, run the page twice — once with the bills at zero and the room split, once with the rent at zero and the equal split — and add the two.
Shares are rounded to the cent, so three shares of {{$100}} come out as {{$33.33}} each and one cent goes unassigned; someone pays it.

Spotted a mistake? Tell us

Rent Split FAQ

: There are three common answers and the page does all of them. Equally, when the rooms and incomes are similar. By room, weighting a bigger or en-suite room above a smaller one, when the rooms differ. By income, so each person pays the same share of their earnings, when the incomes differ a lot — common for couples. Fair is whichever rule everyone accepts in advance.
: Add everyone's monthly income, work out each person's percentage of that total, and apply the percentage to the rent and bills. Two people on {{$5000}} and {{$3000}} share {{$2000}} of rent as 62.5% and 37.5%: {{$1250}} and {{$750}}. Choose 'In proportion to income' and enter each income.
: Usually by room, since the couple's room is one room: a common approach is to weight the couple's room 1.5 or so against 1 for the single room, so the couple pays 60% and the roommate 40% of the rent. Bills, which scale with people, are often split per head instead — three ways with the couple paying two shares.
: Rent tends to follow the room and bills tend to follow the people, so many households use a room split for rent and an equal split for bills. The page applies one rule to both; run it twice to combine the two.