It’s likely that very few Canadians view completing and filing the annual tax return as anything other than an unpleasant chore to be endured, with a sigh of relief once it’s finally done. The goal, for both the taxpayer and the Canada Revenue Agency (CRA), is for the return to then be “assessed as filed”, meaning that the CRA agrees with the income information provided, the deductions and credits claimed, and the final overall tax result obtained by the taxpayer. And, while the best-case scenario is for the taxpayer to have filed a return that is correct and complete and filed on time, that’s a result which can be derailed in any number of ways.
By the third week of April 2025, just under 20.5 million returns for the 2024 tax year had been filed by individual Canadians. 95% of those returns were filed using online filing methods (NETFILE or EFILE), meaning that they were prepared using tax return preparation software.
The use of tax preparation software significantly reduces the chance of making an error in the preparation of a tax return, especially clerical or arithmetical errors, like entering a figure on the wrong line of the return form or getting the wrong result when adding a column of figures. The software can also catch instances in which a taxpayer attempts to claim a deduction or credit to which they are not entitled, or situations in which the taxpayer fails to enter all required information needed for the CRA to process the return.
Notwithstanding, no matter how good a particular tax preparation software program is, it can work only with the information that is provided to it. Sometimes taxpayers prepare and file a return, only to later receive a tax information slip or receipt that should have been included on that return. It’s also easy to make an inputting error when transposing figures from an information slip (for example, a T4 slip from one’s employer) into the software, such that $73,246 in income becomes $72,346. Whatever the cause, where the figures input are incorrect or information is missing, those errors or omissions will be reflected in the final (incorrect) result produced by the software.
Whatever the cause or reason for the error or omission in an already filed return, the question which immediately arises is how to make things right. And, no matter what the reason for the error or omission, the course of action to be followed by the taxpayer is the same.
The first impulse of many taxpayers when a mistake or omission is discovered is to file another return, in which the complete and correct information is provided, but that’s not the right answer. There are, however, several ways in which a mistake or omission on an already filed tax return can be corrected, including online options.
And although it seems counterintuitive, the best course of action at least initially is to do nothing. The taxpayer must wait until the CRA has issued a Notice of Assessment with respect to the incorrect return already filed, for the very good reason that the return as filed isn’t in the CRA’s system until then. Once the Notice of Assessment is issued, however, there are three options available to the taxpayer to make the necessary correction.
Taxpayers who are registered for the CRA’s online service “My Account” can avail themselves of the Agency’s online “Change My Return” feature at Change my return: online adjustments for income tax and benefits returns – Canada.ca. The process is quite straightforward – using a drop-down menu, the taxpayer chooses the tax year for which they want to make a change on the return. They can then search for the line number on which the change is needed, or do a text search – for example, a search for “charitable donation”. While most taxpayers will be seeking to make a change/correction only on their return for the 2024 tax year, a Change my Return request made in 2025 can relate to any tax year after 2014.
Once the correct line number is found, a “New Amount” box will appear, into which the correct amount can be input. A summary page will then show the old and new numbers and, if the taxpayer is satisfied that the information is correct, they click on “Submit Changes”. A confirmation number for the changes made is then provided. The CRA will then process the information and issue a new Notice of Assessment which reflects the changes made.
At one time, the process of becoming registered for My Account was somewhat cumbersome, as the taxpayer had to wait about 10 days to receive a CRA issued security code, which was sent by regular mail. That process has been streamlined, and registration for My Account can now be done in real time through what the CRA terms “document verification”. This document verification process requires a user to take a picture of their government-issued photo identification and of themself in order to verify identity. For purposes of this process, the only acceptable photo identification documents are a Canadian passport, Canadian drivers’ licence, or provincial/territorial photo ID card. More information on how to register for My Account using the document verification method can be found on the CRA website at About My Account – CRA account help – Canada.ca.
Taxpayers who are not registered for My Account and do not choose to register, but who have filed their tax return using one of the Agency’s electronic filing services (whether NETFILE or EFILE) can make a correction to their return by using the Agency’s ReFILE service. Like the Change my Return feature, the ReFILE service (available at https://www.canada.ca/en/revenue-agency/services/e-services/e-services-businesses/refile-online-t1-adjustments-efile-service-providers.html) enables taxpayers to make corrections to an already filed return online, on the CRA website.
Essentially, taxpayers whose returns have been filed online (through NETFILE or EFILE) can make a correction using the same tax return preparation software that was used to prepare the return. However, the number of tax years for which a change/correction can be requested is shorter than that available through My Account/Change my Return. Taxpayers who used NETFILE or EFILE to file their 2024 tax return can file an adjustment to a return filed for the 2021, 2022, 2023, or 2024 tax years.
There are other limitations to the ReFILE service. ReFILE cannot be used to make changes to personal information, like the taxpayer’s address, marital status, or direct deposit details. There are also some types of tax matters which cannot be handled through ReFILE, like applying for a disability tax credit or the Canada child benefit.
While using the CRA’s online services, whether through My Account/Change my Return or ReFILE, is certainly the fastest way to make a correction on an already-filed return, taxpayers who don’t wish to use an online method do still have a paper option. The paper form to be used is Form T1-ADJ E (23), which can be found on the CRA website at T1-ADJ T1 Adjustment Request – Canada.ca. Form T1-ADJ E (23) can be used to request a change to a tax return filed for any tax year, once the return for that year has been filed and a Notice of Assessment issued.
Hard copy of a T1-ADJ E (23) (or a letter) is filed by sending the completed document to the appropriate Tax Centre, which is the one with which the tax return was originally filed. A listing of Tax Centres and their addresses can be found on the reverse of Form TD-ADJ E (23). As well, the taxpayer can go to https://www.canada.ca/en/revenue-agency/corporate/contact-information/tax-services-offices-tax-centres.html on the CRA website and select their location from the drop-down menu found there. The address for the correct Tax Centre will then be provided.
Where a taxpayer discovers an error or omission in a return already filed, the impulse is to correct that mistake as soon as possible. However, it’s important to remember that no matter which method is used to make the correction – My Account/Change my Return, ReFILE, or the filing of a T1-ADJ E (23) in hard copy – it’s necessary to wait until the Notice of Assessment for the return already filed is received. Corrections to a return submitted prior to the time that return is assessed simply can’t be processed by the CRA.
The CRA’s goal is to process changes which are requested online within a two-week period. Requests for changes which are sent by mail using Form T1-ADJ (E) 23 take longer – usually about eight weeks. However, a notice on the CRA website indicates that the Agency currently has a significantly higher-than-normal inventory of mail requests, resulting in processing delays for adjustment requests sent by mail.
A summary of the methods by which a tax return can be changed/corrected, which includes links to detailed information on each such method, can be found on the CRA website at How to change your return – Canada.ca.
The information presented is only of a general nature, may omit many details and special rules, is current only as of its published date, and accordingly cannot be regarded as legal or tax advice. Please contact our office for more information on this subject and how it pertains to your specific tax or financial situation.
