Philip Hammond's Budget will be on March 8 - just weeks before Theresa May's deadline for triggering the Brexit process.
The Chancellor will deliver his financial statement in the Commons as the Prime Minister prepares to invoke Article 50, starting the two-year process of talks to leave the European Union.
She has said the formal step will be taken no later than the end of March 2017.
Mr Hammond has previously announced plans to scrap the spring Budget and move it to the autumn, meaning that there will be two full budgets in 2017 to switch to the new timetable.
Mr Hammond used his Autumn Statement in November to announce his shake-up of the way tax and spending changes are announced.
He told MPs: "No other major economy makes hundreds of tax changes twice a year, and neither should we.
"So the spring Budget in a few months will be the final spring Budget.
"Starting in autumn 2017, Britain will have an autumn Budget, announcing tax changes well in advance of the start of the tax year."
In 2018 there will be a spring statement, responding to the Office for Budget Responsibility's forecasts, but it will not be a "major fiscal event".