Millennials are the most likely to buy additional mobile data
Uswitch has revealed that over a quarter of Brits run of smartphone data every other month.
This figure works out to the equivalent of 10 million people having to buy additional data to get through the month.
In total this can add up to £384 million being spent every year on additional data.
The study also found that over six million people use all their data each month, with 2.9 million having to top up within just 10 days.
These smartphone users will spend and average of £17.41 on topping up.
Brighton are the worst offenders when it comes to topping up on additional data. Residents in the coastal city spend an extra £115 on average a year.
Plymouth sits bottom of the areas surveyed, with £43.75 spent, while London residents spend an additional £85.34 on data each year.
According to Uswitch, men are spending 53 per cent more on additional data, at an average top of price of £19.80. This is compared to women, who top up £12.88 on average.
Millennials, perhaps unsurprisingly are the most likely to top up with additional data.
Over half of mobile users (52pc) said they spend their allowance surfing the web, while 47pc regularly use social media sites.
Music streaming is the third most common (30pc), followed by a quarter (24pc) that watch videos, films and TV series.
But nearly seven million people (18pc) use their mobile data to compensate for a slow broadband connection at home, as they choose to switch off Wi-Fi.
Uswitch.com mobiles expert Rehan Ali said: “A quarter of smartphone users are spending millions of pounds to stay connected every year, with many unsure about how much data they have or use every month.
“With many people paying more on topping up, than they do on their monthly plans, consumers are often left suffering bill shock each month as their data top ups soon add up.