Katy Perry’s biggest hits of all time: Billboard counts down top 5, and number-2 may surprise you [WATCH]

Katy Perry is one of the biggest hit-makers in the music business, and she recently made history with her third diamond-certified single — that’s three singles with 10 million equivalent units each based on sales and streaming. No one else has achieved that. But what are the biggest hits of her career so far? Billboard counts down the top five above, and while all three of her diamond singles make the list, the order isn’t necessarily what you would expect.

Billboard’s list is based on Perry’s performance on the Hot 100 singles chart based on an inverse point system giving greater weight to weeks spent at number one and less weight to weeks spent at number-100. Since this list focuses on chart rankings as opposed to specific sales or streaming performance, her diamond singles aren’t ranked one-two-three. Instead, her most recent diamond single, “Roar,” comes in at number-five. It spent just two weeks at number-one in 2013 despite its blockbuster success. followed by “California Gurls” (seven-times platinum) in fourth position — that summer hit spent six weeks on top in 2010.

Then comes Perry’s diamond anthem “Firework” in third place; it was number-one on the Billboard Hot 100 for four weeks between 2010 and 2011. Perhaps more surprising is her number-two single of all-time: “E.T.” featuring Kanye West, which spent five nonconsecutive weeks on top in 2011 and went eight-times platinum, though it’s not quite as iconic as some of her other hits that didn’t make her all-time top-five like “I Kissed a Girl” and “Teenage Dream.”

Last but certainly not least is her biggest hit on the Billboard chart: “Dark Horse” featuring Juicy J. It wasn’t her longest-running number-one hit — it spent four weeks in the top spot in 2014 — but with 13.2 million units, it was the second-biggest hit worldwide that year.

What do you think of Billboard’s list? Are these also Katy Perry’s best songs? Vote in our poll below to let us know which number-one Kate Perry hit is your favorite.

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