Zettabytes overtake petabytes as largest unit of digital measurement

The world's total digital output is the equivalent of all the information that could be stored on 75bn Apple iPads Photo: Reuters

Humanity’s total digital output currently stands at 8,000,000 petabytes - which each represent a million gigabytes - but is expected to pass 1.2 zettabytes this year.

One zettabyte is equal to one million petabytes, or 1,000,000,000,000,000,000,000 individual bytes.

The rapid growth of the “digital universe” has been caused by the explosion of social networking, online video, digital photography and mobile phones.The current size of the world’s digital content is equivalent to all the information that could be stored on 75bn Apple iPads, or the amount that would be generated by everyone in the world posting messages on the microblogging site Twitter constantly for a century.

Around 70 per cent of the world’s digital content is generated by individuals, but it is stored by companies on content-sharing websites such as Flickr and YouTube.

The latest figures were released in the annual survey of the world’s digital output by IDC, the technology consultancy.

The first survey, which was conducted in 2007, estimated that the digital universe was equivalent to 161,000 petabytes.

Adrian MacDonald, vice president of EMC, the IT firm which sponsors the survey, said: "There has been mammoth growth in the types of media that make up the digital universe.

"A huge increase in video and digital photography – in the old days people would take one photograph, now they can knock off 20 photos and rather than store just one, people store all 20. Then there is the fact that the number of devices where information can be generated and stored has also increased."

As a result the digital universe is forecast to expand by a factor of 44 over the next decade, according to the survey.