Telecoms giant now runs five million Wi-Fi hotspots across the UK and Ireland, as mobile users demand more and more smartphone data.
BT has revealed how much data is consumed by people who access its Wi-Fi hotspots.
In the past year, a staggering 13,000,000,000MB - 13 petabytes (PB) - was used by customers who streamed videos, download files and browsed the internet on devices connected to BT Wi-Fi.
13PB is the equivalent of downloading 3.9 billion songs - 150 times more than the entire iTunes music catalogue - or non-stop streaming of The Hobbit in HD for over 1,000 years.
The figures were published as BT announced it now has more than five million Wi-Fi hotspots in place throughout the UK and Ireland.
Andy Baker, chief executive of BT Wi-Fi, said: "The time Wi-Fi users spend online and the amount of data they're using are up across our network.
"People are now so confident and comfortable with their gadgets, we've had to meet the demand with more hotspots in a wider choice of places - on the high street and in thousands of neighbourhoods across the country."
BT's hotspots offer free and unlimited wireless broadband for anyone with BT broadband at home, although a paid service is available to everyone else.
Last month, research by mobile provider O2 found free Wi-Fi can help people conquer their feelings of loneliness. In the survey, 53% of people said they'd happily sit in a cafe alone so long as there was free wireless broadband to entertain them.