Kelly Clarkson's 'Stronger' Becomes Best-Selling Single From An American Idol

Clarkson's chart-topper surpasses Carrie Underwood's 'Before He Cheats' during its 27th week on the charts.

Kelly Clarkson 's chart-topping single "Stronger (What Doesn't Kill You)" has surpassed Carrie Underwood's "Before He Cheats" to become the top-selling single by a contestant from "American Idol," according to Billboard.

The latest numbers from Nielsen SoundScan reveal that "Stronger" has moved 3,510,000 singles as of Thursday (July 5). Since its release in 2006, "Before He Cheats" has shifted 3,509,000 units. Clarkson's achievement is all the more impressive considering it is the track's 27th week on the singles chart and it is still holding strong: After spending three weeks at #1 (the longest run of any of Clarkson's three chart-toppers), the song sits at #21.

"Stronger" has proved to be an across-the-board smash for the original American Idol. The song has enjoyed the pole position on 11 different Billboard charts, and remains in the top spot on the Adult Contemporary tally. But it still has a way to go if it hopes to best Underwood's "Before He Cheats" in terms of chart longevity. "Before He Cheats" spent 64 weeks on the Billboard Hot 100 tally, and in the 54-year history of the chart, only five songs have spent more time on the countdown — led by Jason Mraz's "I'm Yours," which boasted 76 weeks on the chart.

Underwood also boasts better cumulative album sales, but not by much. The country star has sold 13.2 million copies of her four albums, while Clarkson has moved 11.65 million copies of her five records.

Clarkson and Underwood's individual sales, however, far exceed those of any other "Idol" contestant. Season five's Chris Daughtry and season two's Clay Aiken are the only other "Idol's" who can claim career sales of more than five million in the U.S.