Rent payment

How to split the rent between roommates

Rob Whiting
Boom Team

Sharing an apartment with someone can be an amazing experience, and regardless of who you are moving with, rest assured that everybody wants to kick off the new housing experience in a positive way, as well as to avoid arguments about financials.
When it comes to defining the house expenses, you might have some questions, such as “What is the best way to fairly split them?”, “Shall we take into account the common spaces to do the calculation?”.

To ensure that your next housing experience runs smoothly, you should start by finding a fair way to split rent.

Best 5 ways to split rent

Let's first set a couple of apartment examples that we will use to provide a more illustrative explanation of the methods below.

Apartment A

730 sq. ft. apartment | 2 bedrooms and 1 bathroom | Monthly rent: $4.635

Bedroom 1: 215 sq. ft.

Pros: Walk-in closet | Direct sunlight the whole day.

Cons: Its window faces a noisy street.

Bedroom 2: 150 sq. ft.

Pros: It has a door/window that opens to a small balcony, facing the quiet inner yard of the building.

Cons: Doesn't have a closet | In winter it only has direct sunlight for a couple of hours during the morning.

Apartment B

682 sq. ft. apartment | 2 bedrooms and 1 bathroom | The bedrooms are 132 sq. ft. each | Monthly rent: $3.850

Bedroom 1:

Pros: Has a built-in-closet | Has a window facing a quiet street

Cons: It's next to the bathroom, so whenever someone uses it, the person in that bedroom will hear the door, running water, etc.

Bedroom 2:

Pros: Has a walk-in-closet | Has a window facing the inner yard of the building

Cons: It is next to the kitchen, so whenever someone uses it, it's possible to hear some noises.

Now, let’s get to the 5 ways to fairly split rent between roommates.

Split the rent evenly

This is the easiest way. In this case, you divide the total rent evenly between the number of roommates or people, and that’s it.

This method works well when all the bedrooms are the same size (or almost) and have similar perks (such as closet, windows, etc.)

For this case, let’s base our calculations on Apartment B described above. Both bedrooms are 132 sq. ft. each and have similar pros and cons. The monthly rent for the apartment is $3.850.
To split rent evenly, the 2 roommates have to divide the rent by 2 to get the amount each one has to pay each month.

  • Formula: monthly rent/number of roommates
  • Example: $3.850/2= $1.925/each

Split rent by floor space

It is one of the best alternatives if the bedrooms have different sizes, or some of them have private amenities, such as a bathroom, balcony, walk-in closet, and whatnot. Here, the roommates should split the rent evenly by square footage.

To do it, each one has to add the square footage of their private spaces (including private bathroom, closet, balcony, etc.).

Then, divide each roommate’s private space by the total square footage of private space in the apartment (this means that you won’t include common areas, such as the kitchen and living room).

The result is that each person will pay the percentage of the rent that corresponds to the amount of private space each one occupies.

Based on Apartment A, we have the following general formulas:

  1. Bedroom 1 sq ft + Bedroom 2 sq. ft. = total sq. ft. of private space
  2. Each bedroom sq. ft./total sq. ft. of private space = % of the rent that each roommate has to pay

Now, let’s put this in numbers:

  1. 215 sq. ft. + 150 sq. ft. = 365 sq. ft.
  2. Bedroom 1: 215 sq. ft. / 365 sq. ft. = 0,59. Meaning that roommate number 1 will pay 59% of the rent.

Bedroom 2: 150 sq. ft. / 365 sq. ft. = 0,41. Meaning that roommate number 2 will pay 41% of the rent.

Split rent by income

This method is mostly used by couples or friends when one or some of them have a significantly higher income than the other. The idea is to split rent so everyone pays what they can afford. Since this method is mostly based on a personal agreement, there is no definitive formula to split the rent. However, it can help to add the income of each person, and then divide yours by the total income of the household, to get the percentage of the rent you can afford. The general rule is that you should not pay more than 30% of your income for rent.

If this is the method you and your roommates want to choose, you could have some side arrangements. For instance, the roommate that pays less, volunteers to take care of an extra duty of the household, for example, taking out the garbage, cooking one meal X time(s) a week, watering the plants, etc.

Here is an example based on Apartment A:

  • Monthly rent: $4.635
  • Monthly net salary of Roommate 1 = $4.235
  • Monthly net salary of Roommate 2 = $4.815
  • Total income of the household: $4.235 + $4.815 = $9.050
  • % of rent for Roommate 1: $4.235 / $9.050 = 0,47 → 47%
  • % of rent for Roommate 2: $ 4.815 / $9.050 = 0,53 → 53%

Split rent by perks access/proximity

If the rooms have similar sizes, or there is a bigger one with a small disadvantage, such as lack of windows, scarce natural light, faces towards a noisy street. Or if on the contrary, one of them has access to a nice private balcony or has a walk-in closet, it’s good to take those perks or disadvantages into account when doing the calculation, regardless of whether you are going to use any of the methods on this list.

If you are doing the calculations by square footage, but the biggest bedroom is not the best in terms of perks, privacy, etc. Then, it might be worth discussing it all together and perhaps agree on paying a little bit less or more.

Based on Apartment B described above, we have the following example with “a discount” for the room who has more disadvantages:

The bedrooms are 132 sq. ft. each.

Monthly rent: $3.850.

Bedroom 1 has a built-in-closet, while Bedroom 2 has a walk-in closet, which is nicer. The bedrooms are 132 sq. ft. each, so the easiest method would be to split the rent evenly. However, the walk-in closet in Bedroom 2 provides more storage space, and therefore, both roommates agreed to discount $100 of the monthly rent that corresponds to Bedroom 1.

Formula: monthly rent/number of roommates

Example: $3:850/2= $1.925/each

$100 discount for Bedroom 1: $1.925 - $100= $1.825

Split rent using Sperner’s Iemma

"Sperner's Lemma" was discovered in 1928 by a mathematician called Emanuel Sperner, but it was applied to the housing matter by Dr. Francis Su, a math professor at Harvey Mudd College in California, who in 1999 published a paper titled “Rental Harmony: Sperner’s Lemma in Fair Division”.

It’s not the easiest way to split the rent, but it is the best method to do it based on metrics that aim to divide the rent fairly, taking into consideration a key factor: the personal preference of each roommate. It might sound confusing that you can apply metrics into something very subjective as personal preferences, but it is not that complicated to apply it. The New York Times has explained it in a very illustrative way.

What are the best online tools to split the rent?

For those who prefer a more straightforward process, a good choice for splitting household expenses is to use an online tool or calculator. These tools will help you divide the expenses according to the total rent, room sizes, and amenities. Here are some of them:

Check out these five methods together with your partner or roommates. It will surely help you avoid fights about rent division. Also, make sure to check this again from time to time with your roommates in case the method that you have chosen in the beginning doesn’t fit anymore.


Tips to split rent with a couple

When it comes to living together with roommates and one of them wants to bring his/her significant other to live in the same apartment, it is important to set the rules in advance, to avoid misunderstandings and keep a nice coexistence.

Set boundaries before moving-in

From the usage of common areas to schedules, tolerance to noises or music, etc. The best is not to assume what you think is fair, good, or bad. It is better to settle down the expectations, as well as to make things clear.

Take into consideration the space occupied and home usage

When choosing one of the five methods to fairly split rent with a couple explained above, it is also important to consider the room sizes and the usage of common areas. It is better not to assume or impose that as there is a couple, they should pay more for their room than the others. There are other factors to take into mind. For example, what if the couple doesn’t spend much time in the apartment, and therefore, they barely use the living room or the kitchen? The best is always to try to concede some points to your roommates, to gain others.

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