Science graduates in America have come up with a way that lets people calculate what friends and relatives owe them.

Buxfer, short for ''bucks transfer'' is a social-networking site with a personal-finance focus.

It lets users form groups of friends or housemates and keeps track of who owes what for expenses; for example- utility bills, dinner tabs, pub tabs and any other shared expenses.

The online device also allows room mates to track collective expenses over long periods of time, for example if a housemate pays for dinner and a movie for everyone, they can earn credits in a Buxfer group and therefore pay less than his roomies on the next month's utility bills.

In addition, Buxfer can be configured to e-mail the users groups about new transactions and payments. When the user logs into Buxfer, icons on the home page hshow how much is owed. Friends can also leave notes for each other on the site.

Started seven years ago as a website for the creator’s friends and colleagues, the website was released into the public domain in September this year and is free to use.

In the future Buxfer, aims to help users track belongings, such as books and DVDs, lent to friends and let them report expenses via SMS text message.

The creators are also working on a similar feature that will eventually allow users to enter and receive data from a mobile phones or PDA’s.