The average Kiwi household's data usage is doubling almost every year watching shows like Unbreakable Kimmy Schmidt.

It's no surprise the rise of online TV has seen Kiwis chewing through internet data faster than ever, but just how much we're using may raise a few eyebrows.

Chorus has found the average user on its network is now using 150 gigabytes per month, which was 50 per cent higher than the June 2016 average.

The average Orcon customer's use was another 60 per cent higher at 240GB, and the internet service provider predicted the New Zealand average will double again by the end of 2018.

MIKE BLAKE/REUTERS Netflix alone accounted for a quarter of all Orcon traffic.

This means a monthly average of 1 terabyte is just around the corner.

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To put that in context, it would take 416 standard-definition Netflix episodes to burn through 1TB of data.

That's so much TV it would take a single person about 21 days, without sleep, to watch.

Palmerston North was one of the most data-hungry cities in New Zealand on both networks. The average home used 168GB of data in April, 46 per cent more than they were using a year ago, or 276GB for Orcon customers.

Karamea Miller has always considered herself a heavy internet user, especially since she racked up an $867 mobile phone bill while her family's home connection was on the fritz last month.

She used to feel a bit guilty about how much of her free time, in-between work and study at Massey University, was spent watching a screen. But that was until she found out how much data other people used.

Between herself and her parents the Miller household used 60GB a month, over 100GB less than the average Palmerston North home.

"I watch a lot of Netflix and Youtube, [but] 168GB? That's an overwhelming amount of data. They most be watching a lot more...I don't feel bad anymore."

The data used by Longburn Adventist College year-13 pupil Arni Agar and his mum would probably blow Miller's mind.

The pair are ahead of Orcon's predictions and already use around 1TB a month. And they don't even have ultra-fast broadband yet.

Agar said they had a 4K resolution TV, so most of the data was sucked up by streaming shows in high-definition.

"I do have a web development business, so I run a server. But it's only for two or three websites so it doesn't use all that much. The bulk of it is streaming, downloading and a bit of gaming."

Chorus network strategy manager Kurt Rodgers said online streaming services were one of the biggest drivers of the increase in data consumption.

"As more content becomes available online, new devices are released to watch it on and higher video resolutions such as 4K, and eventually 8K, [we will] see increasing pressure on the bandwidth required at peak times."

Orcon general manager Taryn Hamilton said online TV was the fastest growing type of traffic on Orcon's network. In fact Netflix alone accounted for a quarter of all Orcon traffic.

How much streaming was responsible for the growth in internet traffic was made clear by how the biggest spikes in data consumption came in winter, when shows like Game of Thrones and The Walking Dead dropped new series.