Updated Checked by the Tax-Services.ca editorial team How we check
Whoever prepares your tax return in London, Ontario, you’re the one answerable for what’s on it. The CRA says so in plain words. So before you hand over a single slip, decide what you want from a tax preparer and what you’ll check on the way out.
If you came here looking for one named firm, such as Liberty Tax, we can’t tell you about its prices, offices or hours. We couldn’t confirm any of that, and we won’t guess. What we can give you is a way to judge any preparer, on any street in the city.
What is a tax preparer, in the CRA’s eyes?
The CRA uses the term loosely. A preparer can be a firm, an organization, a discounter or any other certified individual who files returns for other people. It keeps a directory of certified preparers that you can search by postal code, which is a fair place to start if you know your part of London but not the names.
Ontario adds no special step. Federal and Ontario tax are worked out the same way with a storefront, an accountant or software at your kitchen table. What you’re paying for is time, care and someone to answer questions, not a better tax rate.
What should you have in hand when you leave?
Four things change hands in an ordinary visit. This table shows what to expect and why each one matters.
| Item | What the CRA says |
|---|---|
| Form T183, Part F | You sign it to let the preparer send your return electronically. The figures on it must match the electronic return. |
| A copy of your return | You review it before it goes. You’re responsible for its accuracy. |
| Notice of assessment | The CRA usually processes an electronic return within about 2 weeks. |
| Slips, receipts and the T183 | Keep them for at least 6 years. |
How can you sanity check a preparer’s numbers?
Do a rough run yourself before the appointment. It takes five minutes and it stops you nodding along at a figure that’s off.
Say you earn $85,000 in employment income and live in Ontario. The income tax calculator gives $15,551.05 in federal and Ontario tax, and $5,769.52 in CPP and EI, which leaves $63,679.43. Your own return will differ, since medical costs, donations and RRSP deductions all move it. But if a preparer’s answer lands thousands away from that, ask where the gap comes from.
Refund is the other number people care about. Put your withholding into the tax refund calculator and you’ll know roughly what’s coming before anyone tells you.
Running a small business or freelancing? A net income of $45,000 in Ontario means about $10,060.99 in tax and CPP together, according to the self-employed tax calculator. That tool leaves out EI and GST/HST, so treat it as a floor.
What about a refund advance?
The CRA describes a discounter as a business that works out your expected refund and pays you one lump sum up front, before your return is filed. That can feel like a favour. It’s a loan against money the CRA owes you, so ask what it costs, in dollars, and who keeps the difference. We couldn’t confirm what any London firm charges for this, so get the number in writing.
Where do people go wrong with a tax preparer?
Most of the trouble comes from a handful of habits. Signing a blank form is the worst. Never do it, and take home a copy of the return every time.
The CRA also warns about preparers who offer claims you don’t qualify for, like donations you never made or child care you never paid. The refund looks great, then a review letter arrives, and the bill lands on you, not on them.
Skip the questions and you’ll pay for it too. Ask how the fee is set, whether the price changes if you have a T5 or rental income, and who answers if the CRA writes six months later. A good preparer answers without fuss.
Finally, check that the numbers on the T183 match the return you reviewed. The CRA says they must.
Is a preparer worth it at all?
For a plain T4 return, probably not. Certified software does the job, and the guide to choosing tax software covers how to pick one. A preparer earns the fee when your year was messy: self-employment, rental income, a move, or a return you’re catching up on. If you wonder how much your deductions matter, try the tax credits calculator before you pay anyone to find them.
Where the numbers come from
Deadlines, the preparer directory, Form T183 and the six year record rule come from the Canada Revenue Agency’s pages, read in September 2026. The tax figures come from the 2026 federal and Ontario rates used by our calculators. This site has no link with the CRA or any preparer.
Frequently asked questions
Who is responsible for my return if a preparer files it?
You are. The CRA says you carry responsibility for the accuracy of the return, so read it before you authorize filing.
What is Form T183?
It's the form you sign, in Part F, to let a preparer send your return to the CRA electronically. Its figures must match the electronic return.
Can I find a certified preparer near me?
Yes. The CRA runs a tax preparer directory you can search by postal code.
How long should I keep my slips and receipts?
At least 6 years, along with the completed T183.
Do prices differ between London firms?
Probably, but we couldn't confirm any firm's fees. Ask for the price in writing, and ask what triggers extra charges.
- How to choose a tax preparer in Canada
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
- Ontario income tax and sales tax in 2026
How Ontario income tax works in 2026: the five brackets, the surtax and health premium, the 13% HST, and the calculators that switch to Ontario
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.