Rent Split Calculator
Four ways to divide the rent, shown side by side, so you can argue about the method rather than the maths.
Heating and internet are used equally regardless of room size.
Room size can be any unit, as long as everyone uses the same one. Only the ratios matter.
Household total
$2,240.00
Who pays what
Every method compared
Everything here runs on your device. Nothing you enter is uploaded or stored.
Enter the rent, the shared bills and everyone’s details, and this divides the total four different ways at once. The method you pick sets the headline figures, but the comparison table always shows what the other three would have produced — because in most households the disagreement is about which method to use, not about the arithmetic.
How to use it
- Enter the total monthly rent, then any shared utilities as a separate amount.
- Add each housemate with their name, room size, monthly income and nights per week in residence.
- Choose the split method. The results update immediately.
- Decide whether utilities are shared evenly or in proportion to rent.
- Read the comparison table to see every method at once, then press Copy link to send it round.
Room size can be in any unit — square feet, square metres, or even a rough score out of ten — as long as everyone uses the same one. Only the ratios matter.
“Fair” is a choice, not a calculation
The reason rent splitting causes arguments is that people assume there is a correct answer waiting to be computed. There is not. There are several internally consistent definitions of fairness, they produce materially different numbers, and picking between them is a negotiation rather than a sum.
By room size is the most widely accepted, because it divides the rent in proportion to what each person actually receives. If one bedroom is 14 square metres and another is 9, the first occupant gets 55% more space and pays 55% more. It is easy to verify with a tape measure, which is a genuine virtue when trust is limited. Its weakness is that it ignores everything except floor area: a small room with an en-suite and a bay window may be worth more than a large room facing a wall.
By income treats rent as a proportional burden rather than a purchase. Someone earning $4,000 a month and someone earning $2,000 pay in a 2:1 ratio, so both give up the same share of what they have. This is common between couples and rare between friends, because it requires disclosing your salary to your housemates and it means paying more for the same room. It also creates a perverse incentive: a pay rise costs you rent.
By nights per week handles the increasingly common case of someone who works away, stays with a partner half the week, or keeps the room as a base. Charging for five sevenths of a week when you use five sevenths of it is defensible, though most landlords would point out the room is unavailable to anyone else regardless.
Evenly is the simplest and is genuinely correct when the rooms are near-identical. Its honesty is that it makes no claim to nuance.
What makes this tool useful is the comparison table, which shows how much the choice is worth to each person. In a typical three-bedroom house the gap between the cheapest and most expensive method for one individual is often $80 to $150 a month. Knowing that number before the conversation changes the conversation, and the tool names whoever the decision affects most.
What it does not do
It splits money, not rooms. It cannot tell you who should get the big bedroom, and it does not attempt the harder problem of pricing features like an en-suite, a balcony or street noise — for that, some households run a sealed-bid auction on the rooms and use the bids as the weights. Deposits are usually held per person and are not modelled here. It also assumes one rent figure for one period, so mid-month move-ins need pro-rating separately.
Everything runs in your browser. The household details are saved to your own device’s local storage and are never uploaded.
Example: $2,000 rent, three housemates
| Method | Alex (14m², $3,200) | Sam (11m², $2,600) | Jo (9m², $2,900) |
|---|---|---|---|
| Evenly | $666.67 | $666.67 | $666.66 |
| By room size | $823.53 | $647.06 | $529.41 |
| By income | $735.63 | $597.70 | $666.67 |
Room sizes total 34 units, so the largest bedroom carries 14/34 of the rent. Note how the income method moves Jo above Sam despite having the smallest room — that reversal is exactly why the method has to be agreed before the numbers are.
Which method suits which household
| Situation | Usual choice |
|---|---|
| Rooms of clearly different sizes | Room size |
| Near-identical rooms | Evenly |
| Couple with different earnings | Income |
| One housemate away midweek | Nights per week |
| Rooms differ by features, not area | Sealed-bid auction on rooms |
Questions
What is the fairest way to split rent?
There is no single answer, which is the honest position. Splitting by room size is the most widely accepted because it divides what people actually receive. Income-based splitting is defensible between partners but contentious between friends, and even splitting is simplest when rooms are similar.
Should utilities be split the same way as rent?
Usually not. Heating, water and internet are consumed roughly equally regardless of bedroom size, so an even split is the common convention even in houses where rent is proportional. This calculator lets you choose.
Do the shares always add up exactly?
Yes. Proportional splits rarely divide into whole cents, so the remainder is distributed to the largest fractional shares rather than rounded away. The parts always sum to the exact total, which is what makes the figures checkable.
How should we handle a partner moving in?
The nights-per-week method covers part-time occupancy directly. For a permanent additional occupant, most households recalculate the whole split treating them as a full housemate sharing their partner's room.
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