The pop star earned an estimated $US83 million before taxes between June 2017 and June 2018, largely due to her 80-date Witness tour and judging duties on ABC's American Idol reboot, the financial magazine said.

Perry reclaims the spot from 2015, when she earned $US135 million during Forbes' scoring period.

Perry was followed by Taylor Swift, who rose from last year's No 3 spot by earning $US80 million thanks to her Reputation tour. Swift might have unseated Perry this year had most of her tour dates fallen inside the scoring period.

Beyonce, who topped the list last year, came in at No 3 with $US60 million. After welcoming twins Rumi and Sir with husband Jay-Z in June 2017, Bey laid low until her acclaimed Beychella performance at the Coachella music festival in April.

The power couple embarked on their On the Run II stadium tour - a follow-up to their widely successful 2014 joint tour - in June, so much of the tour's earnings fall into next year's scoring period.

That means Beyonce and Swift will likely vie for Forbes' nominal title next year.

Rounding out the top 10 are Pink ($US52 million), Lady Gaga ($US50 million), Jennifer Lopez ($US47 million), Rihanna ($US37.5 million), European superstar Helene Fischer ($US32 million), Celine Dion ($US31 million) and Britney Spears ($US30 million).

Australian Associated Press