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Yes, you can still file a 2020 tax return in Canada. The CRA lets you send initial returns for tax years 2018 through 2025 electronically with tax software certified for the year you’re filing, and the service page lists a window that runs to 29 January 2027. Older years than that go on paper.
How do you file a 2020 tax return in Canada now?
There are three routes, and the software one is the quickest. The catch is that the program must be certified for 2020 itself. This year’s version of TurboTax, for example, or of any other product, won’t do it. You’d need the edition built for that tax year, and you’ll have to check with the provider which one that is.
| Route | Years it covers | What the CRA says |
|---|---|---|
| NETFILE with certified software | 2018 to 2025 for initial returns | Window open until 29 January 2027 |
| Registered preparer using EFILE | The current year and the first seven prior years | The preparer sends it for a fee |
| Paper return | Any year, from the tax package for that year | Usually processed within 12 weeks |
Tax packages for past years sit on canada.ca, going back to 1985. Each one has the guide, the return and the provincial forms, so a paper 2020 return uses the 2020 forms, never this year’s.
What do you need to gather first?
Start with your 2020 slips: T4s from each employer, T5s for investment income, and any receipts for RRSP contributions, tuition or medical costs. If something has gone missing, sign in to your CRA account and see what the CRA has on file for that year. Your old employer or bank can reissue a slip too.
Be honest about 2020. It was a strange year for a lot of people, with CERB payments and a spring spent at home, and those payments get reported too. If you got benefits that year, check that the slip is in the pile before you start.
What does filing late cost?
Only late returns with tax owing get a penalty. It’s 5% of the balance owing plus 1% for every full month late, up to 12 months. And if the CRA charged you a late-filing penalty in any of the previous three years, it’s 10% plus 2% a month, up to 20 months. Interest builds on top of that. It’s compounded daily from the day after the due date.
Suppose the balance for that old year is $2,000. The figures below are plain arithmetic on the CRA’s percentages, and they leave out interest.
| Months late | Standard penalty | Repeat penalty |
|---|---|---|
| 1 | 6% = $120 | 12% = $240 |
| 6 | 11% = $220 | 22% = $440 |
| 12 | 17% = $340 | 34% = $680 |
| 20 (repeat only) | Stops at 12 months | 50% = $1,000 |
For a 2020 return, you’re well past every one of those caps, so the penalty is already at its maximum. What still moves is interest. That’s why a small balance is worth filing sooner and not later. A return with nothing owing doesn’t draw this penalty, though the CRA’s page doesn’t spell that case out, and we’d rather say so than guess.
Take Sam in Regina, who owes $800 on that old return and has never filed late before. The most the standard penalty can reach is 17%, which is $136. A repeat filer with the same balance would face up to 34%, or $272. Not nothing, but a lot smaller than the dread of the unopened envelope.
Can you change a 2020 return you already filed?
Often, yes. You can generally ask for a change to a return for a tax year ending in any of the 10 previous calendar years. A request made in 2026 has to relate to a year after 2015, so 2020 is inside the limit. You can use Change my return in your CRA account or send form T1-ADJ by mail. ReFILE won’t help here, since it covers 2022 to 2025 only.
What can go wrong with a return for a past year?
Using the wrong year’s forms is the classic. Rates, credit amounts and even line numbers shift every year, and a return built on this year’s forms will be wrong from the first page.
The calculators on this site use 2026 rates. Don’t feed them 2020 income and expect a 2020 answer. They’re still handy for today’s questions, such as the tax refund calculator for the current year, the income tax calculator for a fresh estimate, or the tax installments calculator if unfiled years are behind a habit of owing.
And what about benefits and credits for a year you filed late? The rules weren’t confirmed on a page we could read, so there’s no guessing here. Ask the CRA, or check your notice of assessment after you file.
Also keep the slips. If a T4 or a receipt from that year is gone, your CRA account may still show slips the CRA has on file. Whether every slip is there is something to check on your own account.
What this page is based on
The filing years, the service window, the penalty percentages and the change limit come from the Canada Revenue Agency‘s pages on certified software, NETFILE, EFILE, late-filing penalties and changing a return, read in September 2026. The arithmetic in the penalty table is ours. This is an independent guide, separate from any government body.
Frequently asked questions
Can I still file a 2020 return online?
The CRA lists NETFILE for initial returns from 2018 to 2025, using software certified for that year, with a window that runs to 29 January 2027.
Can I use this year's software for 2020?
No. The software has to be certified for the specific tax year you're filing.
What's the late-filing penalty?
5% of the balance owing plus 1% for each full month late, up to 12 months. If you were penalized in the last three years it's 10% plus 2% a month, up to 20 months.
Is there a penalty if I owe nothing?
The CRA's page describes the penalty as applying to a balance owing. It doesn't spell out the no-balance case, so confirm with the CRA.
Can I change a 2020 return that I already filed?
Generally yes. A request made in 2026 must relate to a year after 2015, and ReFILE covers 2022 to 2025 only.
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