The Dean of Norwich, the Very Reverend Graham Smith, made the announcement eight years after the appeal started.
Funds raised during the campaign have already paid for a restaurant on the site of a medieval refectory destroyed by Henry VIII.
Work is also due to start this autumn on an education centre on the site of a medieval lodging house.
Campaign manager Henry Cator said: "I believe these two buildings will put Norwich Cathedral in the premier division of cathedrals in the country.
"It is thanks to the enormous support from people, not only in terms of money, but in time and enthusiasm."
Mr Cator raised £45,000 by driving a vintage Rolls Royce across China in 2000, a year after the campaign was launched.
Other money-making events included charity auctions and a pantomime appearance by the Bishop of Norwich at the city's Theatre Royal.
The refectory, which has won several design awards, opened in 2004.
The education centre will be on the same site as the medieval hostry, which was an inn or lodging house.
It was here that the monks would provide hospitality and medical treatment for visitors.
The Norwich Cathedral campaign finally reached the £10m mark thanks to a £400,000 legacy from a local benefactor.