John gave 26.8m pound to charity last year, mainly to his Aids foundations in Britain and the US which he established in 1992.
Rowling donated 10.3m pound, according to the Sunday Times.
The writer's charities of choice were the Lumos Foundation, her own charity aimed at closing down all child institutions and orphanages around the world by 2050, as well as the Volant Charitable Trust, which raises money to alleviate social deprivation and for research into multiple sclerosis, which killed Rowling's mother.
Other celebs that made the list include footballer David Beckham, who donated 5m pound to children's charities. Another athlete on the list was Northern Irish golfer Rory McIlroy, who donated 1m pound and Colin Montgomerie with 0.9m pound.
Jamie Oliver was named seventh most generous celebrity in the poll, having donated 1.4m pound towards his own charitable organisation including the chef apprentice programme he started in 2002.