The Harry Potter series has earned $6.4 billion at the global box office and the last film hits theaters this summer. Between the films, books, merchandise and amusement park at Universal Studios in Orlando, Fla., Rowling is worth $1 billion. If she never comes up with another good idea, she will be able to collect Harry Potter money for the rest of her life. Rowling wrote the first Potter books while a single mother living on welfare. She wrote the last book in the upscale Balmoral Hotel in Edinburgh, Scotland. The Harry Potter author swithers between millionaire and billionaire status. Not because the 51-year-old buys too many racehorses and yachts but because she gives so much of her cash away. Last December (2016), she dropped off American magazine Forbes’ billionaires’ list, with UK taxes and charitable donations blamed. Last year, she gave £10.3million to her charity Lumos, who aim to get children out of orphanages in eastern Europe and to further multiple sclerosis research. Her mother had MS and Rowling has founded a clinic at Edinburgh University in her name. Rowling’s fortune did not come easily. As a single parent, she pushed her baby to cafes and stretched one coffee over hours as she wrote her first book. When her daughter needed a nappy change, she popped into a branch of Boots that had free nappies in the toilets. The bulk of her wealth has come from the books, reckoned to have made her £900million. Film rights, licensing and and Harry Potter theme parks are also lucrative. With her west end stage production, Harry Potter and the Cursed Child, winning nine Olivier awards this week, the Edinburgh-based author is unlikely to be off the Forbes’ list for long.