Being on the wrong tariff costs average phone user £194 a year.
UK mobile phone users are wasting £5 billion a year by being on the wrong tariff, claims price comparison site Bill Monitor.
There are over seven million mobile phone deals on the market and being on the wrong one costs each person an average of £194 year, the site's research shows.
Over a fifth of mobile users (21 per cent) said they regularly exceed their monthly limits, resulting in penalty charges of between £5 and £40, the survey revealed.
Unsurprisingly, with three quarters using devices to browse the internet, extra charges for data allowance are a common occurrence.
Mobile users fork out £173 million in additional data allowance charges every year. Forty-seven per cent of smartphone owners said this was because they were unaware of how much data they can use each month.
Social networking applications, such as Twitter and Facebook, were pinpointed as particularly problematic because they use up data even when they are in the background.
The findings also revealed that users are often unaware of how much data they are consuming – as many struggle to quantify 1MB.
Only 12 per cent of respondents knew how much it would cost to download 1MB of data outside of their allowance.
Carphone Warehouse, which commissioned the research, said it plans to help customers cut their wastage by matching them up to better contracts.
Andrew Harrison, CEO of Carphone Warehouse Europe and the Geek Squad, said: “We’ll compare every network and phone combination and give independent advice on which deal is best.
"The cost of data charges is a growing issue and this is only going to increase as more people convert to smartphones," he added.