Courtesy of New York magazine.

Courtesy of New York magazine.

When sharing an apartment or group house, it only seems fair that those in bigger rooms should pay a higher share of the rent. But, how do you factor in features like more windows, a fireplace, or a bigger closet?

Miller Samuel’s Jonathan Miller (who used to do an amazing job analyzing the DC market) takes a stab at how to calculate a fair rent split in an article for New York magazine out today.

For the article, Miller looks at a two-bedroom apartment with a rent of $3,200 a month.

Miller advocates for dividing the rent by square footage as proportionally as possible. In the example given, room A is 225 square feet, while room B is 175 square feet; this breaks down to a 9/7 ratio. By our calculations, that comes to $1,800 for roommate A and $1,400 for roommate B. (Roommate A is responsible for 56.25 percent of the rent, and roommate B for 43.75 percent.)

If one bedroom has an attached bathroom, said Miller, that should be worth about 2 percent of the monthly rent, or $64 in the example. In the article, room B has a bathroom, so the divide changes: roommate A pays $1,736, and roommate B pays $1,464.

From there, other square-footage adding amenities, like a bigger closet or a terrace, need to be factored in. Miller offers a few equations to help crunch the numbers in a fair manner. After that, various life-enhancing amenities may warrant slight adjustments. For example, a fireplace might with worth about $25 dollars more a month.

While this approach may require you breaking out the TI-82, the fairness of the final result may ultimately mitigate tensions among roommates. Readers, how do you go about dividing up the rent?