Once a struggling single mother, J.K. Rowling's life changed forever in 1990 when she conjured up the idea for the Harry Potter series while on a train from Manchester to London. The author is now one of the world's wealthiest writers, with an estimated fortune of $1 billion (£753m), thanks to the magical universe she has created.

Since the first Harry Potter novel hit shelves in 1997, the beloved franchise has grown into a multi-faceted, multibillion-dollar enterprise – in fact, we doubt even the wizarding bank Gringotts has a vault big enough to stash away all the cash it has accumulated. By our calculations, the overall Harry Potter franchise is worth at least $43.19 billion (£32.5bn). From the books to movies and even theme park rides, read on to discover which branch of the sprawling Harry Potter empire is the most lucrative. All dollar values in US dollars.