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Choosing a big or small accounting firm comes down to what your business needs done, not to prestige. An owner-run shop with a handful of employees rarely needs a national firm’s reach. A company with foreign subsidiaries, outside investors and a lender asking for reviewed statements may outgrow a two-person practice within a couple of years, and that’s the moment to start looking around. No official source ranks the two, so this page sticks to how to decide.
What actually differs between the two?
Size changes who does the work, how fast they answer and what it costs you to be a small client. That’s about it. Both kinds of firm are bound by the same tax law and the same professional rules, so a small practice isn’t a lesser one.
The table lists the questions worth asking each firm, rather than claims about either type.
| What to ask | Why it matters |
|---|---|
| Who prepares my file, and who reviews it? | You may meet a partner once and deal with a junior all year |
| Who covers if my accountant is away? | A one-person practice may have nobody |
| Have you handled my industry and province? | Rules differ for a contractor, a restaurant, a shop |
| How is the fee set: fixed, hourly, monthly? | Surprise bills come from vague scopes |
| What do I have to send you, and by when? | Late records cause late filings |
When does a small firm fit?
If your books are simple, one owner, one province, a few customers, a local practice is often enough. You’re likely to talk to the person who signs your return. Ask for that in writing if it matters to you.
Think of Colette, who owns a two-chair hair salon in Sudbury. She wants someone who knows her name, answers a text and doesn’t need an hour to remember her situation. A small practice gives her that. A national firm would see her as a rounding error.
The trade-off is capacity. A small office can get swamped in the weeks before a filing deadline, and your questions may wait. It’s fair to ask how many clients each accountant carries.
When would a large firm make sense?
Think of jobs that need several specialists at once: a sale of the company, a group of related corporations, cross-border payroll, or an audit that lenders or investors demand. One person can’t cover all that, and a bigger firm has departments for it.
If you don’t have that kind of file, be honest about it. Paying for a team you never use is a poor trade. Fees depend on the firm and the work, so ask for a written quote from each one you’re considering and compare what’s inside it.
One myth is worth clearing up. A big name doesn’t mean your own file gets extra oversight. The Canadian Public Accountability Board inspects firms that audit public companies, and it doesn’t assess audits of private companies or not-for-profits, so for a typical small business the firm’s size changes nothing there.
How can you test a firm before you hire it?
Start with something small. Give them last year’s return or your bookkeeping question and see how they respond. Do they explain in plain words? Do they ask for the documents they need, or guess?
Check the basics too. Ask for the accountant’s professional designation and look it up with the provincial body that issues it. Ask how they handle your records and how long they keep them.
Use a few numbers of your own as a test. Ask what tax your corporation should expect on a given profit, then compare with the corporate tax calculator. If the answers are far apart, ask why. There may be a good reason, like a year end or a related company, and a good accountant will say what it is.
What mistakes do owners make when picking?
The most common one is hiring on price alone, then finding out the quote left out payroll or GST/HST filing. Read the scope. Payroll deductions are their own job, and the payroll remittance calculator shows what you’ll owe each period if you’re paying staff.
The second is switching too late. If a firm keeps missing your questions, move before year end rather than after a missed deadline. And the third is expecting an accountant to fix a shoebox of receipts for free. Keep your records tidy, and the bill stays smaller.
Before signing, work out what the service must earn you. The profit margin calculator shows how much extra revenue you need to cover a higher fee at your margin, which is a useful ballpark check. As a quick example, if your margin is 10% and one firm costs $2,000 a year more than another, you’d need about $20,000 in extra sales just to break even on that difference ($2,000 divided by 0.10).
Some owners want to see the wider set of tools first. The business tax calculators collect them in one place.
What if you outgrow a small firm, or a big one outgrows you?
It happens, and it’s not a failure on either side. Signs you’ve outgrown a small practice: you’re hiring across provinces, a lender wants reviewed statements, or you’re planning to sell. Signs a big firm no longer fits: you can’t reach anyone senior, every question is billed, and your file changes hands each year.
When you move, plan the handover. Ask your old firm for the working papers and a full copy of your filed returns, and give the new one a clean list of open items. The CRA says you stay responsible for keeping adequate records even when an accountant keeps them for you, per its guide to keeping records, so make sure your own copy is complete before the old firm closes your file. Our guide to choosing a tax preparer covers the personal-tax side of switching.
What this page is based on
This page has few figures on purpose. Where it uses tax numbers, they come from the calculators here, which follow 2026 federal and provincial data, as checked on 29 September 2026. The CPAB point comes from the board’s published inspection information. Nothing on fees or firm size could be confirmed from an official source, so it’s left out. No government body has reviewed or endorsed what you read here.
Frequently asked questions
Are small accounting firms less qualified?
No. Size says nothing about a designation. Look up the accountant with the provincial body that issues it.
Do large firms cost more?
We couldn't confirm fee levels from an official source. Get written quotes and compare what each one includes.
Can I start small and move later?
Yes. Many owners change firms as the business grows. Ask for your records in a usable format first.
Who will actually do my work?
Ask before you sign. At any size, find out who prepares the file and who reviews it.
When do I need an audit?
When a lender, investor, or law asks for one. We didn't confirm any threshold here, so check your corporate statute or agreement.
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