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To prepare for tax season with your accountant, gather your slips and receipts early and tell them what changed in your year. For the 2025 return, the filing date for most people was April 30, 2026, and self-employed people had until June 15, 2026 to file, though any tax owing was still due April 30. The CRA hasn’t published the dates for the 2026 return yet.
Today is the end of September, so you have time. February is when the crowd arrives, and the accountants who answer emails in a day in October may take a week in March.
What should you gather before booking a meeting?
Start with what changed. A new job, a move, a baby, a sold property, a side business, a death in the family. Write those down first, because the accountant can’t guess them from a stack of slips.
Then collect the paper. Employers issue T4 slips and must file them by the last day of February, so those show up early. Bank and investment slips can arrive later. Add last year’s return and notice of assessment, plus receipts for anything you plan to claim.
If you run a business, add the year’s sales and expenses, your GST/HST filings and any payroll remittances. The bookkeeping schedule we wrote about makes this step far shorter.
| Item | 2025 return date | Note |
|---|---|---|
| T4 slips from employers | Last day of February 2026 | Slips for the 2026 year are due in February 2027 |
| RRSP contributions for 2025 | March 2, 2026 | First 60 days of the year |
| Return and tax owing | April 30, 2026 | Most people |
| Return, self-employed | June 15, 2026 | Tax owing was still due April 30 |
| Instalments | March 15, June 15, September 15, December 15 | Only if you owe enough |
How much will an RRSP contribution change my tax?
It’s the one question worth asking before the year ends, and it works best with a real figure. Say you earn $85,000 in employment income in Ontario. The income tax calculator shows $15,551 in federal and Ontario tax, and $5,770 in CPP and EI.
Now enter a $5,000 deduction. Tax falls to $14,069, so the contribution saves about $1,483. That’s roughly 30 cents back on each dollar, at that income.
Two cautions. Neither is small, and both change what you should do with the answer. The calculator uses 2026 tax data, so treat the result as a guide for the year now running, not the return you filed in spring. And your own room matters: the CRA’s dollar limit is $32,490 for 2025 and $33,810 for 2026, but your limit is what’s on your notice of assessment. Try the RRSP calculator if you want to test other amounts.
What if I’m self-employed and owe tax in April?
Here’s a trap. The June 15 deadline for filing feels like breathing room, but the payment date didn’t move. Any tax owing was due April 30, and paying late is how a manageable bill gets bigger.
Take net business income of $60,000 in Ontario. The self-employed tax calculator shows $7,879 of income tax and $6,724 of CPP, for $14,603 in all. It leaves out GST/HST, EI and business expenses, so it’s a starting point.
If you expect to owe more than the calculator’s $3,000 threshold, ask your accountant about instalments. The instalments calculator splits a $6,000 bill into four payments of $1,500. Ask which method to use, since the CRA also allows other ones based on last year’s figures.
What do I say in the first email?
Keep it short.
Say which years you need help with, what changed, what you’re sending, and the one thing you’re worried about. Attach documents as searchable files, named so that a stranger opening the folder at eleven at night, tired and behind on other clients, could still sort them without a phone call.
Don’t hold back the awkward item. An unreported side income or a lost slip doesn’t get easier with time. Our tips on talking to your accountant go into more detail.
What mistakes make tax season harder?
Waiting for every slip before you call.
It feels tidy, but you can start with what you have and add the rest as slips arrive.
Another is trusting a figure you didn’t check. Slips can be wrong, and so can old carry-forward numbers, so compare them against your own records. Keep those records for six years from the end of the last tax year they relate to.
Last, don’t assume a date. If a page quotes a 2026 return deadline as fixed, we couldn’t confirm it, and neither could the source we checked. Look at the CRA’s own page in the new year.
Where the numbers come from
Dates come from the Canada Revenue Agency’s 2026 tax deadlines page, which covers the 2025 return, and its RRSP and TFSA limits page. The RRSP deadline for the 2026 tax year isn’t printed by the CRA, so we don’t show it. Calculator results use our 2026 federal and Ontario tables and are estimates.
Frequently asked questions
When is the tax season deadline in Canada?
For the 2025 return, April 30, 2026 for most people and June 15, 2026 for the self-employed. The 2026 return dates aren't published yet.
Does a self-employed person pay tax on June 15?
No. Tax owing for 2025 was due April 30, 2026, even though the return could be filed by June 15.
When are T4 slips due?
Employers must file T4 information returns by the last day of February after the calendar year.
What should I send my accountant first?
Last year's return and assessment, your slips, receipts for claims, and a short list of what changed in your year.
How long should I keep my tax records?
Six years from the end of the last tax year they relate to, unless the CRA allows you to destroy them earlier.
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How to decide if you need a tax preparer, what a preparer does, the questions to ask before you hire one and where to find free help in Canada
Information only. This page is general information, not tax, legal or accounting advice. Tax-Services.ca is an independent publisher: we don't prepare or file tax returns or offer tax services, and we have no connection with the CRA, Revenu Québec, any government or any company named on this page. Check the figures that matter with an official source or a qualified professional.