# How should our rent split work?

A rent split calculator for roommates: shares the rent by bedroom size with the shared space split evenly, by income, or evenly.

- Page: https://www.acalculator.org/everyday-life/rent-split-calculator
- JSON spec: https://www.acalculator.org/everyday-life/rent-split-calculator.json
- Version: 3696484a73e1

## Default answer

Example with the default inputs (Monthly rent $2,400.00, Split By room size, Whole home size 1,100, Bedroom sizes [Room size 180; Room size 140; Room size 110]): For $2,400.00 a month: Person 1: $880.00; Person 2: $792.73; Person 3: $727.27.

## Inputs

| Key | Label | Description |
| --- | --- | --- |
| rent | Monthly rent | The total rent for the home each month. |
| by | Split | By bedroom size, by income, or evenly. |
| area | Whole home size | The floor area of the whole home, in the same unit as the rooms (sq ft or m²). |
| rooms | Bedroom sizes | One row per person: the floor area of their own room, in sq ft or m². |
| incomes | Incomes | One row per person: their income, all for the same period. |
| people | People | How many people share the rent. |

## Outputs

| Key | Label | Description |
| --- | --- | --- |
| split | Who pays what | Each person’s monthly share of the rent. |
| most | Highest share | The largest share. |
| least | Lowest share | The smallest share. |
| shared | Shared space | Whole home size − all bedrooms, split evenly (by room size only). |
| rate | Rent per unit of area | Rent ÷ whole home size (by room size only). |

## Method

By room size: share = rent × (own room + (home − all rooms) ÷ people) ÷ home; by income: share = rent × income ÷ all incomes; evenly: rent ÷ people.

## Assumptions

- By room size, every square foot costs the same and the shared space (kitchen, living room, halls) is split evenly.
- Shares are shown to the cent, so the shown shares can differ from the rent by a cent.
- Bathrooms, parking or a balcony used by one person are not priced separately.

## Worked examples

1. rent = $2,400.00, by = rooms, area = 1,100, rooms = {"size":180} or {"size":140} gives split = Person 1: $880.00; Person 2: $792.73; Person 3: $727.27, shared = 670, most = $880.00, least = $727.27. Source: FairSplit, The Room Size Rent Splitting Method (common space split equally, private space split by each bedroom’s share of the square footage), https://usefairsplit.com/guides/how-to-split-rent-by-room-size/ (retrieved 2026-10-03).
2. rent = $2,400.00, by = income, incomes = {"income":60000} or {"income":45000} gives split = Person 1: $1,066.67; Person 2: $800.00; Person 3: $533.33, least = $533.33.
3. rent = $1,850.00, by = even, people = 2 gives split = Person 1: $925.00; Person 2: $925.00, most = $925.00.

## FAQ

### How do you split rent by room size?

Take the whole home’s floor area and subtract the bedrooms to get the shared space, and split that evenly. Each person’s area is their bedroom plus their part of the shared space; their rent is that area ÷ the whole home × the rent.

### How much does each roommate pay in the example?

For $2,400 and 1,100 sq ft with bedrooms of 180, 140 and 110 sq ft, the shared space is 670 sq ft, 223.33 each. The shares are $880.00, $792.73 and $727.27, which add up to $2,400.

### How do you split rent by income?

Each person pays rent × their income ÷ everyone’s income added up. With incomes of $60,000, $45,000 and $30,000, the shares of $2,400 are $1,066.67, $800.00 and $533.33.

### What if I do not know the size of the whole home?

Check the listing or the lease, or measure each room and add a rough figure for the kitchen, living room and halls. Use the same unit, square feet or square meters, everywhere.

### Should a room with its own bathroom pay more?

Often, yes. This calculator prices floor area only; you can add an en-suite bathroom’s area to that person’s room size, or agree a fixed amount on top.

### How is this related to splitting a bill?

It is one use of the bill split calculator: the rent is a bill shared by the same people every month, split by room size or income instead of by what each person ordered.

## Sources

- FairSplit, The Room Size Rent Splitting Method (common space split equally between roommates, private space split by each bedroom’s share of the square footage). https://usefairsplit.com/guides/how-to-split-rent-by-room-size/ (retrieved 2026-10-03)