How to Split Roommate Costs Evenly
No two bedrooms are exactly alike. If you’ve found a Tandem apartment that you and your roommate love, but you think you should have to pay more or less for whatever reason, then you should take a look at this roommate calculator from the New York Times.
If you’ve ever rented a room with others, you’ve probably faced the dilemma of which room each person should take and how much they should pay for it, considering some rooms might be bigger or better than others. This New York Times calculator, based on a mathematical theory of fair division, comes to the rescue.
Enter the total rent and the number of roommates. Then, each each person is proposed different prices for the rooms available and chooses based on what seems fair to him/her. The calculator repeats this several times for each person, switching up the proposed amounts until everyone is satisfied.
The calculator is based on a mathematical theory called Sperner’s Lemma, and the creators describe it this way:
The division method used here is designed to produce an “envy-free” division of the rooms of a shared apartment, i.e. no one will want to swap their room and price for someone else’s.
With each decision about which room to take at different prices, the algorithm becomes more accurate. It learns more about how much each roommate likes each room and narrows the range of prices it thinks might be fair.
If you and your potential roommates find you can’t agree even after using the calculator, however, you might want to look for a different apartment (or different roommates).