The announcement came at an event hosted by Instagram chief Kevin Systrom announcing a new feature enabling users to share long-form videos up to one hour long.
“We have now a community of one billion users,” Systrom told the event in San Francisco.
Instagram becomes the fourth Facebook platform to hit the billion-user mark, including the namesake social network with more than two billion users, and the WhatsApp and Messenger services.
“Since our launch in 2010, we’ve watched with amazement as the community has flourished and grown,” Systrom said in a blog post.
“This is a major accomplishment.”
Instagram has been outpacing rival social networks such as Twitter and Snapchat and has been gaining younger users even as Facebook itself has seen declines in the youth segment.
In September, Instagram said it had some 800 million monthly active users.
Systrom announced the launch of the IGTV platform which will have a separate smartphone app or can be watched from Instagram.
“The way we are watching video is changing,” Systrom told the event.
IGTV will enable any user to upload long-form videos and will also include “channels” from video “creators,” similar to a format employed by Google-owned YouTube.
“Anyone can be a creator — you can upload your own IGTV videos in the app or on the web to start your own channel,” Systrom said.
Systrom said IGTV is built to be used on a smartphone, and boosts the time for videos from the previous limit of one minute.
Facebook acquired Instagram in April 2012 for a combination of cash and stock worth some $1 billion at the time.
While Facebook offers no detailed revenue breakdown, the research firm eMarketer estimates Instagram will generate $5.48 billion in net US ad revenue this year, up 70.4 percent from last year and accounting for more than one-fourth of Facebook’s net mobile ad revenue.