The annual tax return will be scrapped in favour of a digital account in a bid to cut costs and boost efficiency, George Osborne is expected to announce.
The Chancellor will unveil the measure in his final Budget speech of this Parliament, due to start at 12.30pm today.
Osborne is expected to explain that the new digital self-assessment will slash the time millions of taxpayers and small businesses will take – from 40 minutes to just 10 minutes a year.
The account will be available on a range of devices, including PCs, smartphones and iPads.
The Treasury said the current system is "complex, costly and time-consuming" and explained that users will be able to see how HM Revenue & Customs calculates their taxes once they log into the new system.
The government said the switch from the current system to the digital form will be completed by the end of the decade.
The Treasury also explained that five million small firms and 10 million taxpayers will have access to the new system early next year.
In addition, the first group of customers will no longer have to fill in an annual tax return by 2017 if they favour the new system.