Why use this calculator
Splitting rent evenly is the default because it needs no conversation, and it is also the method most likely to leave someone quietly resentful. Bedrooms in a share house are rarely close in size or quality: the difference between a 150 square foot room with a window seat and a 90 square foot box with a shared wall is real money, and people notice it every month for a year.
Splitting by floor area fixes that, but it ignores the other thing housemates argue about, which is that identical rooms are not equally affordable on very different incomes. This calculator computes both, plus a blend, plus the even split, so the group can see the actual dollar consequence of each rule before anyone signs a tenancy agreement. Deciding the method in advance is what turns an awkward negotiation into arithmetic.
How to use it
- Enter the total monthly rent from the tenancy agreement, not the advertised weekly figure and not your share of it.
- Choose how many bedrooms are occupied, counting a couple sharing one room as a single share.
- Pick the split method you want as the headline, knowing that the comparison table still shows all four.
- Measure each bedroom wall to wall including its built-in wardrobe and enter the floor areas; any consistent unit works because the calculation uses ratios rather than absolute area.
- Enter each person's gross annual income if you intend to use the income or blended method, or leave the defaults if you are only interested in the size split.
- Finally, add up the kitchen, living room, hallways and shared bathrooms and enter that as the shared floor area, which is divided equally between everyone.
What each result means
- Total living space
- All bedrooms plus shared areas added together. It is the denominator the size-based split divides against.
- Bedroom 1 share
- What the person in bedroom one pays each month under the selected method, with the difference from an even split noted.
- Bedroom 1 percentage
- That person's share as a percentage of total rent, which is the number to write into a house agreement.
- Bedroom 2 share
- What the person in bedroom two pays each month under the selected method, with the difference from an even split noted.
- Bedroom 2 percentage
- That person's share as a percentage of total rent, which is the number to write into a house agreement.
- Bedroom 3 share
- What the person in bedroom three pays each month under the selected method, with the difference from an even split noted.
- Bedroom 3 percentage
- That person's share as a percentage of total rent, which is the number to write into a house agreement.
- Bedroom 4 share
- What the person in bedroom four pays each month under the selected method, with the difference from an even split noted.
- Bedroom 4 percentage
- That person's share as a percentage of total rent, which is the number to write into a house agreement.
- Bedroom 5 share
- What the person in bedroom five pays each month under the selected method, with the difference from an even split noted.
- Bedroom 5 percentage
- That person's share as a percentage of total rent, which is the number to write into a house agreement.
- Even split for comparison
- Total rent divided by the number of people, the baseline every other method is measured against.
- Gap between highest and lowest share
- The distance between the largest and smallest payment. A wide gap needs the reasoning written down before anyone signs.
- Shared space per person
- Common area divided equally between everyone, added to each private room before the size split is calculated.
- Rent per square foot
- Total rent divided by total floor area. Useful for comparing this house against others on the market.
- Rent against combined income
- Annual rent as a percentage of the household's combined gross income, measured against the 30% housing stress benchmark.
The formula
The size method gives each person a weight of
w = private bedroom area + shared area ÷ number of people
Then charges share = rent × w ÷ Σw, so private space is paid for in proportion and common space is paid for equally
The income method uses weight = that person's gross income
So share = rent × income ÷ total household income
The blend averages the two fractions: share = rent × (size fraction + income fraction) ÷ 2
The even split is simply rent ÷ number of people. Every method sums to exactly the total rent.
How this number is used in practice
Size-based splitting is the norm in professional share housing because it is defensible. The person with the largest room pays the most, the person in the box room pays the least, and the kitchen and living room are paid for equally because everyone uses them equally.
The practical refinement is that raw floor area is not the whole story: a private ensuite, a balcony, a north-facing window, street noise, or being the room next to the laundry all shift the fair price. The usual approach is to run the size split first, then apply an agreed premium or discount of five to ten per cent for the obvious differences, and check the totals still add up to the rent.
Income-weighted splitting appears most often in two situations: a couple sharing with a single person on a much lower salary, and friends where one is a student or between jobs. It is fairer in the sense that it equalises the burden rather than the payment, but it requires everyone to disclose their income and to re-negotiate when someone changes jobs, which many households would rather avoid.
The blended method exists because it captures most of the fairness of both without making either the sole determinant. Whichever rule you pick, write the resulting dollar figures and the review date into a simple house agreement. The argument is almost never about the method, it is about the fact that nobody remembers agreeing to it.
One number worth checking whatever method you use is rent against combined gross income. Housing agencies in the United States, United Kingdom and Australia all treat roughly thirty per cent of gross income as the threshold above which a household is under housing stress. A share house well above that line is one lost job away from a problem, and it is better to know that before signing a twelve month lease than in month seven.
Worked examples
$2,400 across three bedrooms of 150, 120 and 100 sq ft with 200 sq ft shared, split by size
Bedroom one pays $912.28, bedroom two $785.96 and bedroom three $701.75. A spread of $210.53.
The same house split by income on $95,000, $78,000 and $62,000
Bedroom one pays $970.21, bedroom two $796.60 and bedroom three $633.19. A wider spread of $337.02.
Two housemates on $1,800 with rooms of 180 and 140 sq ft and 300 sq ft shared
The larger room pays $958.06 and the smaller $841.94, against an even split of $900.00 each.
Four sharers on $3,200 splitting evenly rather than by size
Everyone pays exactly $800 regardless of room size, and the size table shows who is subsidising whom.
When people use it
- New housemates agreeing a fair split before signing a lease
- Re-pricing rooms when someone moves out and the group shuffles bedrooms
- A couple sharing with a single person who has a much smaller room
- Setting a sublet or spare-room price that matches what the room is actually worth
- Checking whether a share house is inside the 30% housing stress benchmark
Tips
- Agree the method before anyone picks a room. Choosing the rule first removes almost all of the friction.
- Add a five to ten per cent premium on top of the size split for a private ensuite, and a similar discount for a room with no window or heavy street noise.
- Measure rooms yourself rather than trusting the listing. Advertised floor areas frequently include the wardrobe twice or round up generously.
- Write the agreed dollar figures, the method and a review date into a one-page house agreement that everyone signs.
- Split utilities separately and by usage where you can, because a person who works from home uses noticeably more heating and power.
- Set a review point whenever someone changes job or the lease renews, so the income method does not quietly become unfair.
- Keep the bond or security deposit shares in the same proportions as rent, and record who paid what, or the refund becomes its own argument.
What it assumes, and where it stops being accurate
- Every occupied bedroom counts as one share, so a couple in one room pays a single share and gets the benefit of splitting it privately.
- Shared space is treated as used equally by everyone. If one person has a home office in the living room that assumption is wrong.
- Floor area is used as a proxy for room quality. Ensuites, balconies, aspect, noise and storage are not modelled and need a manual adjustment.
- The income method uses gross income, not income after tax, child support or student loan repayments, so it overstates the capacity of anyone with unusual deductions.
- Utilities, internet, contents insurance and the bond are excluded. Only the rent on the lease is split here.
- The result is a private agreement between housemates, not a legal apportionment. Everyone named on a joint tenancy usually remains liable for the whole rent.
Terms used on this page
- Joint tenancy
- A lease where every tenant is named on one agreement and each is liable for the entire rent, not just their share.
- Housing stress
- Spending more than about 30% of gross household income on housing, a common government affordability threshold.
- Common area
- Space shared by all occupants. Kitchen, living room, hallways and shared bathrooms.
- Bond or security deposit
- Money held against damage and unpaid rent, normally refunded at the end of the tenancy.
Questions people ask
- What actually counts as shared floor area?
- Kitchen, living and dining rooms, hallways, laundry, any bathroom used by more than one person, plus a balcony or courtyard everybody can access. Leave out a private ensuite, which belongs in that bedroom's measurement instead. The shared total is divided equally, because everyone has equal use of it regardless of bedroom size.
- Should the room with an ensuite pay more?
- Yes. The simplest approach is to add the ensuite's floor area to that bedroom's measurement, which automatically raises its share. If that undercounts the value, apply an agreed premium of five to ten per cent to that person's calculated share and reduce everyone else proportionally so the total still equals the rent.
- Is splitting by income fairer than splitting by room size?
- It is fairer in a different sense. Size splitting equalises what you pay for what you get, which is the usual definition of a fair price. Income splitting equalises the burden, so the person earning least is not paying an unmanageable share. Neither is objectively correct, which is why the blended method exists and why the table shows all four.
- How do we handle a couple sharing one bedroom?
- Count them as one share of the room, because they occupy one bedroom. Some houses add a modest surcharge of five to ten per cent because two people put more load on the kitchen, bathroom and utilities, then split the rest of the house normally. Agree that surcharge explicitly rather than assuming it.
- Does the split work in square metres?
- Yes. Every method uses ratios, so the units cancel out entirely. Enter every room in square metres instead of square feet and the shares are identical. Only the rent per square foot result changes meaning, and it then reads as rent per square metre instead.
- Are we each only liable for our own share?
- Usually not. On a joint tenancy every named tenant is jointly and severally liable for the whole rent, so if a housemate stops paying the landlord can pursue the others for the shortfall. A private split agreement governs what you owe each other, not what you owe the landlord. Check your local tenancy rules before relying on it.
Use this with
Rent Split Calculator answers one part of the question. These pick up where it stops: Rent Affordability Calculator, Weekly to Calendar-Month Rent Calculator (AU), Rent vs. Buy Calculator and Budget Planner Calculator.
Where these figures come from
This calculation is jurisdiction-neutral arithmetic. No country-specific rules are applied.
- GOV.UK: Private renting. Tenant and joint tenancy rights in England and Wales
- US Department of Housing and Urban Development. Housing programs, affordability standards and rental data
- ASIC Moneysmart. Independent Australian guidance on borrowing, budgeting and home ownership
Rent Split Calculator produces an estimate for general information. It is not financial, tax, medical, legal or engineering advice. read the full disclaimer. Spotted a wrong number? Report it and it gets fixed. The form picks up this calculator and the inputs you used.