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A tax agent is someone you let deal with the CRA for you. Most people mean that, though some use the words for whoever prepares their return. Here we mean the first: a person who can call the CRA about your account, read your notices and answer questions in your name. You give that permission yourself, and the CRA says signing in to your account is the fastest way to do it.
What can a tax agent do for you?
Once you authorize a representative, the CRA can talk to that person about your tax account. The CRA page says access can come by phone, mail, fax or in person, depending on how you set it up. That covers the boring parts of a tax problem: a letter you don’t understand, a missing slip, a balance owing that looks wrong.
It doesn’t change what you owe. No agent can bend a rule for you, and anyone who says otherwise is selling something you shouldn’t buy. What an agent can do is spot a claim you missed, answer the CRA faster than you would, and keep track of dates. If you just want to file a plain return once a year, you probably don’t need one at all.
How do you authorize a tax agent?
There are three routes on the CRA’s authorization page. The method decides what kind of access the person gets.
| Route | What you do | What to know |
|---|---|---|
| Your CRA account | Sign in, open Profile, add the representative | The CRA calls this the fastest way |
| Agent asks first | The agent sends a request through Represent a Client using a RepID | You confirm or deny it in My Account |
| Form AUT-01 | Sign the form and mail it to the CRA tax centre named on it | Slowest. Send it within six months of signing. Offline access only |
A few details on the paper form are worth knowing. You need a separate form for each representative. It gives access by phone, mail, fax and in person, but not online access, and it doesn’t give the person a view of your file in Represent a Client. If your agent works online, use the account route instead.
The CRA also describes levels of access you can grant. We couldn’t confirm the full list of levels from that page, so read that section before you click anything. Pick the narrowest one. Simple.
Do you need a tax agent, or just a better estimate?
Ask what problem you’re solving. If it’s “what will I owe?”, run the numbers first. The income tax calculator gives you a figure in a minute, and the tax refund calculator shows whether the tax already withheld is enough. If the result looks close to what you expected, an agent has little to add.
If instead you’ve got a notice, several income types, or a business, that’s where a person earns their keep. And if you’re self-employed, the self-employed tax calculator shows how much to set aside before you hire anyone.
What is a missed deduction worth?
Here’s a way to judge whether an agent’s help pays for itself. Take someone in Ontario with $70,000 of employment income. Our calculator puts their federal and Ontario income tax at $11,134. Suppose an agent finds $5,000 in deductions they’d overlooked. The same calculator now shows $9,651, a saving of about $1,482.
That’s the ceiling for one missed item, and it needs a real deduction behind it, with paper to prove it if the CRA ever asks. So before you agree to any fee, ask what the person expects to find and how they’d prove it. A saving of $1,482 doesn’t justify a fee near that size. We didn’t find any official fee levels, so we can’t tell you what’s normal.
Where do authorizations go wrong?
The common one is forgetting. You give access for a single problem, the problem ends, and the person still has access a year later. Check your account profile now and then and remove anyone you’re no longer working with.
Another is handing over more than you meant to. If someone asks for your online banking or CRA sign-in details, don’t give them. The proper route is authorization, so the person uses their own credentials and you can see who has access.
Third, mixing up two jobs. Authorizing an agent to deal with the CRA isn’t the same as having them prepare your return, and the CRA asks you to review a prepared return and Form T183 before you approve it. Keep your slips, receipts and the completed T183 for at least six years. That advice is on the CRA page about using a professional tax preparer.
And an authorization can quietly lapse on paper if it never reaches the right place. The AUT-01 has to arrive at the tax centre listed on the form within six months of your signature.
Where the numbers come from
The rules on authorizing a representative and on tax preparers come from Canada Revenue Agency pages read in September 2026. The example uses the 2026 federal and Ontario rates built into our calculators, which take their data from CRA sources. Nothing here is a tax opinion, and we have no link with the CRA. Two things stay open: the exact access levels, and what agents charge.
Frequently asked questions
Does a tax agent have to be authorized to speak to the CRA?
Yes. The CRA talks to a representative about your account only after you give authorization, online, by their request or on Form AUT-01.
What is the fastest way to authorize someone?
The CRA lists signing in to your account and adding a representative under Profile as the fastest way. The mailed form is the slowest.
Can I authorize two people on one form?
No. The CRA says you need a separate AUT-01 for each representative.
How long do I have to mail Form AUT-01?
Send it to the tax centre listed on the form within six months of the date you sign it.
What should I keep after a preparer files for me?
Your tax slips, receipts and the completed Form T183, for at least six years, according to the CRA.
- How Canadian income tax works: brackets and credits
How federal and provincial Canadian income tax stack up, what marginal and average rates mean, and how credits and deductions change your bill
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.