People who have been forced to work from home during lockdown could be owed £280.
The Money Saving Expert revealed the information in the latest weekly newsletter that thousands of people subscribe to.
During the 2020 lockdown millions of people were forced to work from home because of the coronavirus pandemic.
HMRC launched a microservice which let people claim a whole year's tax relief, even if they'd just worked from home for one day.
And now that also applies for the new 2021/22 tax year too, meaning many are due two years' relief, worth up to £280.
MoneySavingExpert said: "These changes are all, of course, driven by the pandemic, which has seen many firms have to close workplaces, sometimes several times, meaning millions of UK staff have been required to work from home temporarily, even if just for part of the week.
"HMRC has specifically confirmed to me that claims from employees working at home due to coronavirus measures, if their usual workplace is closed, count for this relief."
People can claim £6 a week without proof, to help cover the extra costs they incur from working from home such as energy bills.
People who pay the basic rate of 20% tax can claim £62.40 a year, those on 40% tax can claim £124.80 a year and those on the highest rate of 45% can claim £140.40 per year.
Meaning that those in the highest tax bracket can claim £280 and those in the 20% bracket can claim £124 for the two years.
The newsletter said: "If you have higher costs due to working from home from April 6 2021 you can claim via the microservice.
"If also claiming for the last tax year (2020/21), you can do both at once.
"If you've already claimed for 2020/21, you must claim again for the 2021/22 tax year, via the same microservice.
"Relief for the current tax year will be paid via a change in your tax code. This is what tells your employer how much tax to take. The result will be less tax taken off each month for the rest of the year."
