The Rent Split by Room Size Calculator divides rent fairly between roommates. Part of the rent — covering shared kitchen, living room and bathrooms — is split equally, and the rest is split in proportion to each bedroom’s square footage.
You choose the equal-share percentage: 0% splits purely by room size, 100% is a straight equal split, and anything in between blends both. It handles up to four bedrooms.
Rent Split by Room Size Calculator
Split rent fairly between roommates: part shared equally for common areas, the rest by bedroom size.
Formula
Paysᵢ = R × c ÷ n + R × (1 − c) × aᵢ ÷ Σa
Where:
- R = total monthly rent
- c = share split equally (as a decimal)
- n = number of bedrooms (people)
- aᵢ = bedroom i’s area; Σa = total bedroom area
How the Calculation Works
Step 1: Split the common-area share equally.
Step 2: Split the rest by each bedroom’s share of the total bedroom area.
Step 3: Add both parts for each person.
Example Calculation
Given: $2,400 rent, 50% shared equally, bedrooms 150, 120 and 100 ft²
- Equal part: $1,200 ÷ 3 = $400 each
- Size part: $1,200 split over 370 ft²
- Bedroom 1: 400 + 1,200 × 150/370 = $886.49
- Bedroom 2: 400 + 1,200 × 120/370 = $789.19
- Bedroom 3: 400 + 1,200 × 100/370 = $724.32
The three amounts add up to $2,400.
Choosing the Equal-Share Percentage
There is no single correct percentage. One way to set it is the share of the home that is common space: if bedrooms make up about half the floor area, a 50% equal share reflects that. Roommates can also adjust for features the calculator doesn’t measure.
- Private bathroom or balcony
- Closet size, windows, noise or light
- A couple sharing one room (they may split that room’s share)
Frequently Asked Questions
How do you split rent by room size?
Divide each bedroom’s area by the total bedroom area and apply that share to the rent (or to the non-shared part of it).
Is splitting rent by square footage fair?
It rewards larger rooms fairly, but shared spaces benefit everyone equally — hence the equal-share option.
How do I measure bedroom size?
Length × width; include the closet if you want it to count.
Can I include utilities?
Add them to the total rent if you want them split the same way, or split them separately.
What about a room with a private bathroom?
Add the bathroom’s area to that bedroom or agree on an extra amount.
