The Billboard Chart, the benchmark for American music sales, will include streaming in its measurements starting next week, to reflect the rapid growth of services such as Spotify.
Billboard Magazine, which produces the weekly charts with tracking company Nielsen SoundScan, described the move as the biggest overhaul in its methodology since 1991, an era when CDs were replacing cassettes.
The change indicates that the music industry is expecting a permanent role for streaming services, despite the objections of a number of musicians - most famously current chart-topper Taylor Swift, who pulled her music from Spotify and complained of unfair compensation to artists.
The Billboard 200, starting with its Dec 3 chart which covers the previous week, will record one album sale for every 1,500 times that songs from a single album are streamed through Spotify or its competitors such as Beats Music, Google Play and Xbox Music.
"The new methodology for the Billboard 200 is a welcome and necessary evolution of Nielsen and Billboard's album chart data," said Darren Stupak, an executive vice-president at Sony, on Wednesday.
"The ways in which fans consume music, and the ways in which music is monetised, have grown beyond the traditional metrics of album sales."
The chart began to look at digital sales of both albums and singles in July 2003 as Apple's iTunes became a major force.
The chart creators said the latest overhaul would also slightly change the focus of the Billboard 200 by measuring how often people listen to the music - not just whether they bought it.
Sweden-based Spotify says it has 50 million subscribers worldwide, including 12.5 million who pay for the premium service which has no advertisements.
Britain's Official Charts Company in July began to add streaming to its Top 40 singles chart, with 100 streams equivalent to one single.