Numerous different tariffs are provided by phone operators
Mathematicians and scientific advisers from Oxford University have helped develop a price comparison website for mobile phone users.
BillMonitor has become the first mobile phone comparison site to be accredited by the communications regulator Ofcom.
The UK mobile market offers consumers more than three million deals on over 119,078 tariffs.
The site is financed by commissions on its recommendations and only takes account of some of the deals on offer.
Consumers supply details of their bills and the website analyses them for a tailored recommendation.
"Science has been put to work for struggling consumers in a free service to help them lower their bills," said Stelios Koundouros, co-founder of BillMonitor.
Ofcom had previously accredited two price comparison websites (covering broadband and digital television), but accepts that there are a number of websites that had not applied for accreditation.
The watchdog Consumer Focus is investigating the state of the mobile phone market after 100,000 complaints were made about services in the last two years.
"The love affair with mobile phones is turning sour. Tariffs are complex and public confidence in the service providers is low," said Ed Mayo, Consumer Focus chief executive.
"Mobile phones are not a luxury but now an essential service and need to be treated as such. Missing out, paying over the odds or being given the run around by companies should no longer be acceptable."