Updated Checked by the Tax-Services.ca editorial team How we check
Studio tax 2021 is what people type when an old return is still outstanding and they want software to finish it. You can still do it. The CRA says NETFILE takes returns for the 2018 to 2025 tax years until January 29, 2027, as long as the program you pick is certified for the year you’re filing.
Can you still file a 2021 return now?
Yes, and sooner is better. The CRA’s NETFILE page lists 2021 among the years you can send electronically, so a return that’s five years late doesn’t have to go on paper. The service closes for this season on January 29, 2027. You can see the list of years on the CRA’s tax software page.
Two things trip people up. First, tax software is certified year by year, so a program that handles 2025 may not handle 2021. Second, a late return with tax owing costs money for every full month it sits. We couldn’t confirm from the pages we read how far back the CRA will pay out an old refund, so don’t count on one without checking your own file.
How do you choose software for an old year?
Start with the CRA’s list of certified software, not a search result. Each product is shown with the years it covers. Programs such as StudioTax turn up in these searches, and we haven’t tested or compared any of them, so we can’t say what one costs or how it behaves.
Before you pay or install anything, ask three plain questions. Does it list 2021 as a supported year? Will it send the return through NETFILE? Can it pull in your slips, or do you type them in? Have your T4s, T5s and receipts for that year on the desk first. If you can’t find a slip, look in your CRA account before you guess.
| Item | What the CRA says |
|---|---|
| Years NETFILE accepts (first returns) | 2018 to 2025 |
| NETFILE open until | January 29, 2027 |
| Late-filing penalty, first time | 5% of balance owing, plus 1% for each full month, up to 12 months |
| Late-filing penalty, repeat | 10% of balance owing, plus 2% a month, up to 20 months |
| Interest on unpaid tax | Compounded daily from the day after the due date, rate reset each quarter |
The penalty rates above are printed on the CRA’s page for the 2025 return. We didn’t find a separate 2021 table, so your notice is the final word.
What does a late 2021 return cost?
Take a person with $80,000 of employment income in Ontario and $12,000 of tax already withheld. Our tax refund calculator shows $2,127.85 still owing on that. It uses 2026 rules, so it’s only a stand-in for a real 2021 figure.
File three full months late and the first-time penalty is 5% plus 3%, so 8% of $2,127.85. That’s $170.23, before any interest. Wait a year and the penalty is 17%, or $361.73. Interest keeps running the whole time.
Now the other side. If the return shows a refund, there’s no balance owing, so no late-filing penalty on it. But the CRA warns that a missing return can hold up your GST/HST credit, Canada child benefit and Old Age Security. That’s often the bigger loss.
What are the steps to file an old return?
- Confirm the year. Check the certified software list for 2021 and note whether NETFILE is allowed for it.
- Collect the slips for that year. Your CRA account may show them, so look before you guess.
- Fill in the return in the software, one slip at a time, and read the summary before you send it.
- Send it by NETFILE if the program offers it, and keep the confirmation number.
- Pay what you owe as soon as you can. Interest runs from the day after the due date, not from the day you file.
Picture Sam in Winnipeg, who skipped 2021 while between jobs and only noticed when a benefit payment went quiet. He doesn’t need to be perfect. He needs the right year’s software, his slips and an afternoon, and the sooner he sends it, the less a late penalty has to grow.
Hold on to the notice of assessment when it arrives. That paper is the proof you filed, and it’s the number your next return leans on.
Which calculators help with an old return?
None of ours carries 2021 rates, so they can’t check the software’s answer. They can tell you roughly what you’re facing. The income tax calculator gives a sense of scale for a year of employment income, and the tax credits calculator shows how deductions and credits change the bill (federal only). If you had business income, try the self-employed tax calculator. It counts CPP but leaves out EI and business expenses.
Mistakes that cost the most
Filing a return with guessed numbers. Slips matter, and the CRA may hold copies that won’t match your guess.
Waiting until you can pay in full. Penalties grow on the balance owing, so file first and pay what you can.
Using this year’s software version for last decade’s return. Check the year on the certified list.
Ignoring a demand to file. Once the CRA sends one and you miss it, the repeat rates can apply to later years too.
Sources, and how we checked them
The NETFILE years, the open dates and the penalty rates come from Canada Revenue Agency pages on filing and late-filing penalties, read in September 2026. The example figure comes from our own calculator on 2026 rules. This site has no link with the CRA or any software maker.
Frequently asked questions
Can I still file a 2021 tax return?
Yes. The CRA lists 2021 among the years NETFILE accepts until January 29, 2027, if your software is certified for that year.
Does any software work for every year?
No. Certification is renewed every year, so check the CRA list for the year you need.
What is the late-filing penalty?
For a first offence it's 5% of the balance owing plus 1% for each full month, up to 12 months. Interest is charged on top.
What if I'm owed a refund on the old return?
There's no balance, so no late-filing penalty. We couldn't confirm how far back the CRA pays refunds, so check your own notice.
Can your calculators do a 2021 return?
No. They use 2026 rates, so they give a rough scale only.
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