---
title: "Rent Split Calculator by Room Size | Shared Willow"
description: "Split rent between housemates by room size: an equal share for the kitchen and living room, premiums for a private bathroom or parking. Exact to the cent."
url: https://sharedwillow.sbs/
---

# Split the rent by room size

Bigger room, bigger share; the kitchen and living room are everyone's. Enter the rent and your rooms, and get a split that adds up to the cent.

## Who pays what

| Room | Size | Room part | Shared part | Pays |
| --- | --- | --- | --- | --- |
| Big room1 person | 16 m²× 1.15 = 18.4 | $784.57 | $240.00 | **$1,024.57** 42.7% |
| Middle room1 person | 12 m² | $511.67 | $240.00 | **$751.67** 31.3% |
| Small room1 person | 9 m² | $383.76 | $240.00 | **$623.76** 26% |
| Total | 37 m² | $1,680.00 | $720.00 | **$2,400.00** |

**Shared spaces.** 30% of $2,400.00 is $720.00, split equally between 3 people (about $240.00 each).

**Rooms.** The other $1,680.00 is split by size, after each room's extras are added: the rooms come to 39.4 weighted m², so each weighted m² costs about $42.64. Big room: 16 × 1.15 = 18.4.

**Rounding.** Every share is rounded to the cent and the leftover cents go to the largest remainders, so the shares add up to exactly $2,400.00.

## How the split works

Rent pays for two things: your own room and the spaces everyone uses. So the calculator splits it in two parts. The **shared part** (the percentage you choose) is divided equally per person, because everyone uses the kitchen the same amount whether their room is big or small. The **room part** is divided in proportion to each room's size. Extras raise a room's size in the sum: with a +15% private bathroom, a 16 m² room counts as 18.4 m².

A couple in one room pays the room's part once and the shared part twice, and the tool shows each person's half.

## Choosing the numbers

There is no single correct percentage. A shared part between 20% and 40% is a reasonable place to start the conversation; raise it if the rooms are similar and the living areas are big, lower it if the rooms differ a lot. Agree the premiums together before anyone sees the result, and measure every room the same way. You can type sizes as *4 x 3.5*, or add the parts of an odd-shaped room: *4x3 + 2x1*.

## Exact to the cent

Each share is worked out exactly, cut down to whole cents, and the few cents left over go to the rooms with the largest fractions (the largest-remainder method). The shares always add up to the rent, so nobody has to cover a rounding gap.

## More for the shared house

Money, chores and the ground rules. Each tool remembers your house in this browser and works offline once loaded.

- [Shared expenses settle-up](https://sharedwillow.sbs/shared-expenses-settle-up/): Track who paid for what and settle up with the fewest payments.
- [Chore wheel & chore chart](https://sharedwillow.sbs/chore-wheel-chart/): A rotating chore wheel and printable weekly chart for the house.
- [House rules template](https://sharedwillow.sbs/house-rules-template/): An editable house agreement for housemates: quiet hours, guests, kitchen, bills.
- [Bill due calendar](https://sharedwillow.sbs/bill-due-calendar/): Every household bill on one calendar, with reminders you can add to your phone.

## Recommended

Two free tools from elsewhere for the admin side of sharing a home.

### Keep sign-up spam out of the house inbox

Grabbing a one-off discount code for furniture or a moving van quote? CleanTempMail gives you a free disposable address with no account, and the inbox deletes itself after three days, so the follow-up newsletters never arrive.

[Get a temporary address](https://cleantempmail.com/)

### Check a rental listing before you pay

Room adverts and payment links from strangers are a favourite of scammers. Look up when a website's domain was registered with WebTraceCheck's free DNS and domain lookup before you send a deposit anywhere.

[Look up a domain](https://webtracecheck.com/dns-lookup)

## Questions

**Is splitting by square footage fair?**

It is a good start, but size is not everything: light, noise, a lock on the door or a shared wall with the bathroom matter too. Use the extras for anything your household agrees is worth more, including negative premiums for drawbacks.

**Should utilities be split the same way?**

Usually not. Bills like internet or heating are better split equally or by use. Add them with the shared expenses settle-up tool instead.

**Is my rent information saved?**

Only in this browser's local storage, so your rooms are there next time. Nothing is sent to a server.