Songs played on services like Spotify, Deezer and Napster are set to feature in the chart, marking the first time positions could be affected without fans paying any money.
The Official Charts Company says 100 plays will equal a single sale.Songs will have to be streamed for a minimum of 30 seconds to qualify.There will also be controls in place to prevent users playing songs too many times to manipulate the rankings.
The initiative reflects the growing popularity of online streaming. The number of streams rose from 100 million each week in January 2013, to 200 million at the beginning of 2014.
Official Charts Company chief executive Martin Talbot has been quoted saying: "Audio streaming has grown at an extraordinary rate over the past year - and the time is now right to take this important step.
"The Official Singles Chart is, and always has been, the most trusted and definitive measure of music tastes".