I've lived in a number of roommate situations, and each one had its own share of rent-splitting rules. Whether it's paying more for the only room with a walk-in closet or getting a discount because the room was the size of one, there are many factors when deciding who pays what share of the rent, but most of the time, we would just agree on a figure and call it a day.
After finding that most roommates split rent in the same friendly-yet-decidedly-unscientific way, a bright mind at Harvard decided to do all the math for us. Astrophysics graduate student Jonathan Bittner has created a simple calculator to figure out how much each roomie should pay. His site, SplitTheRent.org, asks you simple questions about each bedroom, like the general square footage, the size of its closet, and if it has any windows or doors. From there, your answers are plugged into a formula, and the total rent is divided fairly, down to the cent. So easy! And once you know exactly how much everyone owes, you can use other (GeekSugar reader-recommended) sites like BillMonk and WeSplit.It to keep track of who's paying.