Workers on furlough will get 80% of their usual salary for hours not worked, up to £2,500 a month.
The scheme will apply throughout the UK but will be reviewed by the government in January.
Furlough was due to end on October 31 but the Chancellor had already extended it until December 2 after England was placed in a four-week national lockdown.
Speaking today, Mr Sunak said he was now extending furlough until March 2021 "to give businesses security through the winter".
He added: "The security we are providing will protect millions of jobs.”
If you've been told by your boss that you're being furloughed, it is their responsibility to contact HMRC.
This means you shouldn't need to notify the government of any changes to your pay, as your employer will do this for you.
Employers submit information about furloughed workers through an online portal on the HMRC website.
The details they provide will include your salary, so the government can calculate how much furlough pay you should receive.
Firms must continue paying staff wages on the usual payday and claim the funds back.
After contacting HMRC, your employer will be given a grant by the government to cover the appropriate amount of wages for furloughed staff.
Employees who can't work because their workplace has closed due to temporary lockdown measures can be put on furlough.
Workers will need to have been on a payroll by 11.59pm on October 30, 2020 to be furloughed by their employer.
As part of the revised scheme, anyone made redundant after September 23 can also be rehired and put on furlough.
Workers can be on any type of contract, meaning you could still be furloughed if you are part-time or on a contract.
You don't need to have been furloughed before to be eligible for the scheme, and the business you work for doesn't need to have used it before to use it now.
All employers with a UK bank account and UK PAYE schemes can claim the grant.
Furloughed workers will get 80% of their current salary for hours not worked, up to a maximum of £2,500.
You'll also get your usual full salary for any hours you do work during the lockdown period.
If you can't work during lockdown, and you earn a regular salary, you can work out how much you'll get by calculating 80% of your normal pay.
Businesses have to cover National Insurance and employer pension contributions for hours not worked.
Employers are still able to choose to top up employee wages above the scheme grant at their own expense - but they don't have to.
THE furlough scheme has been extended until the end of March 2021 – we explain how to claim and how much money you get.