When you share space with roommates, it only seems fair that those in larger or more desirable rooms should pay a larger percentage of the rent.  To begin, there are multiple ways to determine how rent should be split. Some popular methods include:

Draw a number, then pick in that order
Pick rooms, then adjust prices in a friendly way
Set room prices, then pick rooms
Just pick rooms in a friendly way and split it

So, what makes a room nicer? People have different preferences and priorities.  Some factors that may justify a premium include:

Lots of windows
Bedroom Layout
Large closet
Private Bathroom
Private Balcony

The tricky part is assigning “weights” for the varying importance of factors to different people. For example, roommate A may value a private balcony, where roommate B sees a walk-in closet as a greater asset.  Because there are always going to be differences of opinion, using a calculator tool may be the best solution. A calculator provides a neutral opinion, avoiding haggling and hurt feelings.

A free application, Splitwise.com,  includes a handy rent-splitting tool that takes into account such factors as room size, windows, closets, baths and more. However, this tool does not take into account the “common area”. This can become a factor when one room is significantly larger than the other(s).  Here’s a hypothetical example.  Rent is $2000/month. Bedroom 1 is 9’ x 11’, or 99 square feet. Bedroom 2 is 14’ x 16’, or 224 square feet. Without considering common space, there is a 31-69 ratio, meaning Bedroom 2 would pay $1380/month while Bedroom 1 would only pay $620/month.

In reality, it’s probably fairer to include the common area square feet and then calculate the ratios from there. For example, Rent $2000/month

Total SF 1000
Bedroom 1 has access to 776 sf
Bedroom 2 has access to 901 sf

This creates a 46-54 ratio – Bedroom 1 pays $920 and Bedroom 2 pays $1080

Splitwise.com  takes into account other factors besides just room size. Some of these factors include: no door, private shower, street noise, flights of stairs and double occupancy.  The equations get a bit tricky in that it is difficult to factor how much each factor should be worth.  For a more in depth discussion of how these variables are weighted and to try out this helpful utility visit Splitwise.com.