The next Budget, along with the conclusions of the 2021 Spending Review, will be held on 27 October, Chancellor Rishi Sunak has said.
The review will set out how much money government departments can expect to get over the next three years.
As part of the review, the Treasury has asked departments to identify "at least 5% of savings and efficiencies from their day-to-day budgets".
Mr Sunak said the review would keep finances on "a sustainable path".
Governments usually use the Budget to outline the state of the country's finances and propose tax changes.
It will be Mr Sunak's third Budget since he became chancellor and comes as the UK continues to deal with the financial fallout from the coronavirus pandemic.
It also comes as the government announces what Institute for Fiscal Studies director Paul Johnson called "the biggest tax rising year in many decades" after the prime minister set out tax changes to raise £12bn a year for social care.
The Treasury said that, including the recent health and social care spending announcements, core department spending would grow in real terms "at nearly 4% per year on average" between 2021-2024.
However, the Treasury also said that, due to coronavirus, it wanted to ensure taxpayers' money is well-spent and is therefore asking departments to identify 5% of potential savings.
Announcing the date for the Budget, Mr Sunak said: "Despite the worst economic recession in 300 years, we have not only got people back into work through the Plan for Jobs but continued to deliver on the priorities of the British people.
"At the Spending Review later this year, I will set out how we will continue to invest in public services and drive growth while keeping the public finances on a sustainable path."