TEENS are unfriending Facebook in droves as they move to cooler social media platforms, a new study says.

The percentage of American 13-to-17-year-olds on Mark Zuckerberg’s social network now sits at 51 per cent, down from 71 per cent in 2015.

TheNew York Postreported that new numbers come from a Pew Research survey of teens and technology use, which found that Facebook now trails significantly behind Instagram and Snapchat — which 72 and 69 per cent of teenagers say they use, respectively.

It was a 20 per cent jump for Instagram, which is owned by Facebook, and a 28 per cent pop for Snapchat.

The most popular platform for teens, however, was the video streaming site YouTube, which 85 per cent of teens said they use for music and video.

The dip wasn’t unexpected for Facebook — the social network has struggled to stay relevant with younger audiences as their parents signed up to monitor their child’s social presence and stayed after the kids moved on to the visual nature of Snapchat and Instagram’s picture-based services.

Facebook has attempted to stay relevant by cribbing popular features such as “stories” from Snapchat, but it has done little to move the needle.

The survey found that Facebook was popular among lower-income teens, with 70 per cent of teens living in households earning less than $US30,000 ($A40,000) using Facebook, while only 36 per cent of teens in households that brought in more than $US75,000 ($A99,000) used the platform.

Pew’s survey reported that nearly half of the teens they surveyed say they are using the internet “almost constantly,” up from 24 per cent in 2015, while 90 per cent go online multiple times a day.

But despite being online all day, every day, teens are divided on whether or not their relationships with social media are a good thing.

Pew found that 45 per cent of teens were neutral about social media’s presence in their lives, while 31 per cent called it positive, and 24 said it is negative.