Rudd grew up in Bournemouth and attended Bournemouth School for Girls. As a child she wanted to be a physicist. Her uncle was a physicist, and Rudd joined the British Junior Astronomical Association. She was the only girl in a group of 48 boys, and said she was never allowed to look down the telescope. The male dominated environment of physics made Rudd consider a career in chemistry instead. When she was fourteen, she started to use washing machines and liquidisers to create rare sugars and sugar phosphates. She sold these chemicals through and co-founded Wessex Biochemicals. Rudd was an undergraduate chemistry student at Westfield College, then part of the University of London. After earning her degree, she joined Wessex Biochemicals which employed thirty people before being acquired by Sigma-Aldrich. She compelted her PhD in 1995 which was awarded by the Open University.