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The best time to hire an accountant is before the deadline that worries you, not the week it lands. For a self-employed person that usually means autumn, well ahead of the April 30 payment date and the June 15 filing date. For a corporation the year end sets the clock, because the return is due six months after it.
Which months are busiest, and which are quiet?
Accountants fill up from February to April. Personal returns pile in, and anyone who calls on April 20 gets a rushed job or a polite no. September to November is the calm stretch, and it’s also when you can still change something that affects this year’s tax.
So if you can choose, set up a first meeting in the autumn. You’ll get a proper look at your numbers, and your bookkeeping still has time to be fixed before the year closes. Hiring in April mostly buys you a filing, with very little planning attached.
What are the dates that decide it?
Match your situation to the row below, then count back a few weeks. That’s when to hire.
| You are | Date (2026 rules) |
|---|---|
| Self-employed, tax owing | Pay by April 30 |
| Self-employed, filing | File by June 15 |
| Self-employed, instalments | March 15, June 15, September 15, December 15 |
| Employer with staff | T4 slips by the last day of February |
| Corporation | T2 return within six months of the year end |
| Corporation claiming the small business deduction | Balance due three months after the year end |
| GST/HST annual filer | Three months after the fiscal year end |
Weekends and holidays push a date to the next business day.
Does a corporation follow a different calendar?
Yes, and people miss this all the time. A corporation with a December 31 year end owes its balance by March 31 if it claims the small business deduction, then has until June 30 to file the T2. The tax comes due three months before the paperwork does.
Here’s what that looks like. The corporate tax calculator puts tax on $100,000 of active business income in Ontario at $11,696 for a calendar 2026 year, or 11.7%. That’s $9,000 federal and $2,696 provincial. If your accountant starts in June, you’ve already missed the payment date by three months and interest is running. Start in January or February, and the cheque is ready by March 31.
When should you hire an accountant for the first time?
Earlier than you think. The three moments that matter most come before a deadline of any kind.
One is before you start, or before you incorporate, because the choice of structure changes how you’re taxed for years. Another is your first employee, since payroll brings remittances and slips. Last comes the day your sales grow to the point where GST/HST registration becomes a question. The line is $30,000 of taxable sales in a single quarter or over four quarters in a row, and you have 29 days to register once you cross it, according to the CRA’s general information for GST/HST registrants. Talk to someone before you cross it rather than after.
Waiting until a letter arrives is the expensive option, and there’s no discount for being surprised. Fixing a mistake with the CRA costs more than avoiding one.
What does the timing cost you if you get it wrong?
Take a sole proprietor with $100,000 of net business income in Ontario. The self-employed tax calculator shows $19,044.97 of income tax and $9,292.90 of CPP for both halves, so $28,337.87 in all, or 28.3% of the income. That’s a large bill to meet on April 30 with no warning.
Now say you’d expected to owe $9,000. The tax instalments calculator splits it into four payments of $2,250. Someone who plans early can spread the cash out. Someone who hires in April pays it in one go, and the CRA charges interest on late or short instalments.
What does a good hiring timeline look like?
Work back from your first hard date. If you file as self-employed, the spring crunch is real, so start talking to accountants in October or November, choose one by December, and send your first batch of documents in January. Employers with a calendar-year payroll should have someone lined up before the February T4 deadline. Corporations should start about two months before the year end, so there’s still time to act while it counts.
Two or three short calls is plenty. Ask each person what they’d want from you and when, how they bill, and whether they have room for a new client in your busy month. An accountant who’s full in March is better to know about in October than in March.
Common mistakes with timing
- Waiting for tax slips before you call. Your accountant can start on the books first.
- Handing over a shoebox in March. Books that are sorted in advance cost less to prepare.
- Assuming June 15 also delays the payment. It doesn’t. The balance is still due April 30.
- Forgetting the corporate payment date and only watching the filing date.
Also remember that an accountant can’t fix what wasn’t recorded. If the year is already over, you can still hire, but the choices are narrower. For a bonus or a one-off payment, the bonus tax calculator shows what’s left after tax before you decide how to take it.
What if you’re already late?
Hire anyway, and say so on the first call. Plenty of people come to an accountant with a missed year or two, and the earlier the work starts the less interest piles up. Expect the accountant to ask for old slips, notices and bank statements first, then file in order from the oldest year. Don’t wait for tax time to roll around again. A tidy start in October can leave you filing on time for next spring.
Where this information comes from
Deadlines come from the Canada Revenue Agency‘s 2026 tax deadline pages for businesses and self-employed individuals. Tax examples come from this site’s calculators, which use 2026 federal and provincial data and a prorated Ontario small business rate for a calendar 2026 year. Your own year end and situation can shift the dates. This site is independent of the CRA.
Frequently asked questions
Is it too late to hire an accountant in April?
No, but you'll get a filing rather than planning, and some firms are full. Self-employed people still owe the balance by April 30.
Do self-employed people get extra time?
They can file by June 15, but any tax owing is still due April 30.
When is a corporation's tax return due?
Within six months of the year end. The balance is due earlier, generally two months after the year end, or three months for a corporation claiming the small business deduction.
Should I hire before I start a business?
Yes, if you're choosing between running as an individual or incorporating. The choice affects how you're taxed.
Can an accountant help after the year has ended?
Yes, with filing and clean-up, but options to change that year's tax are limited.
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