The 59-year-old author of The Wasp Factory died last June from gall bladder cancer.
His published will reveals an estate valued at £3,640,011 at the time of his death.
After leaving gifts adding up to £14,000 to friends, Banks instructed that his estate and all future royalties from his works should go to his widow Adele Hartley, 43.
The pair married in a Highland ceremony last March – just weeks after Banks discovered that his cancer was terminal.
His wealth included his £480,000 home in North Queensferry, Fife, and an archive of his own manuscripts which had been valued by auctioneers Bonhams at £300,000.
The bulk of his estate was made of a £2.1m royalties payment. Banks also had around £700,000 cash held in numerous bank accounts. The car enthusiast had a Mini Cooper convertible worth £10,000, an £18,000 BMW saloon, a £5,000 Toyota Yaris and a £1,000 boat.
Banks had included a clause in his will which would have seen his estate pass to the charity Oxfam if his wife had predeceased him.
He left his boat and his Mini Cooper to his long-term friend Leslie McFarlane.
Banks shocked fans in April last year by revealing that he was “officially very poorly”.