When the filing of the required annual tax return goes entirely as planned and hoped, the taxpayer will have prepared a return that is complete and correct and filed that return by the required filing deadline. The Canada Revenue Agency (CRA) will issue a Notice of Assessment indicating that the return is “assessed as filed”, meaning that the CRA agrees with the information filed and the amount of tax payable determined by the taxpayer. While that’s the outcome everyone is hoping for, it’s a result which can be derailed in any number of ways.
By April 19, 2026, around 19.5 million individual income tax returns for the 2025 tax year had been filed with the CRA. And, inevitably, some of those returns contain errors or omissions that must be corrected.
Nearly 95% of the returns which have already been filed for the 2025 tax year were filed by EFILE or NETFILE, meaning that the return was prepared using tax return preparation software. The use of such software significantly reduces the chance of making a clerical or arithmetical error, like entering an amount on the wrong line or adding a column of figures incorrectly. However, no matter how good the software, it can work only with the information that is provided to it. Sometimes taxpayers who file their returns early then receive a tax information slip that should have been included on that return (or, more frequently, locate a tax information slip that had been received but was overlooked). It’s also easy to make an inputting error when transposing figures from an information slip (a T4 from one’s employer, for instance) into the software, such that $76,326 in income becomes $73,626 or $66,326. Whatever the cause, where the figures input are incorrect, or information is missing, those errors or omissions will be reflected in the final (incorrect) tax payable figure produced by the software.
When the error or omission is discovered in a return which has already been filed, the question which immediately arises is how to make things right. The first impulse of many taxpayers is to file another return, in which the complete and correct information is provided, but that’s not the right answer. There are, however, three separate methods by which most mistakes or omissions made in an already filed tax return can be corrected; each such method has its own requirements, limitations, and time frames for processing.
The 95% of return filers who used tax return preparation software to file their return can use that same software to change the return. (All tax return software programs certified for use by the CRA include that option, known as “ReFile”.) The ReFile service is available seven days a week but is offline for maintenance from 3 a.m. to 6 a.m. Eastern Time each day.
The types of changes which can be made using ReFile include the most frequent sources of filing errors, including reporting income (such as a T4 slip or tips), claiming a deduction, credit, or expense (such as childcare or medical costs), or adding a missing tax slip (such as an RRSP contribution receipt). There are, however, limitations to the kinds of changes which can be made to an already filed return online. Specifically, it’s not possible to apply for benefits or credits, make or revise an election, allocate a refund to other CRA accounts, or update personal information, including a mailing or email address, direct deposit information, marital status, or name.
In addition, taxpayers cannot use ReFile to make a change to a return for the 2020 or earlier tax years, a bankruptcy return, an optional T1 return for a deceased taxpayer, a return filed with the incorrect province or territory of residence, or a return for a non-resident. More information on how to make a correction in an already filed return using ReFile can be found on the CRA website at Changing a tax return – Personal income tax – Canada.ca.
The second online option is available to taxpayers who have registered for the CRA’s “My Account” service. Those taxpayers can make a change or correction on their already-filed return using the “Change My Return” feature in My Account. The steps needed to do so are as follows:
- Sign in to your CRA account.
- Select Individual if you are changing your own return or Representative if you are changing someone else’s.
- Select Tax returns.
- Find and select Change my return.
- Select the tax year you want to change and follow the steps.
- Save your confirmation number and summary of changes for your records.
As with ReFile, there are situations in which the Change my Return website feature cannot be used to correct a mistake in an already filed return, including the following:
- A return for the 2015 or earlier tax years;
- A bankruptcy return (or any year before the year of bankruptcy);
- An optional T1 return for a deceased taxpayer;
- A return filed with the incorrect province or territory of residence;
- Certain international and non-resident returns.
Where neither ReFile nor Change my Return can be used to make a correction on an already filed return (or where the taxpayer prefers not to use an online option), filing the request using hard copy to be sent by mail to the CRA is still possible. The paper form to be used is Form T1-ADJ E (23), which can be found on the CRA website at T1 Adjustment Request (canada.ca). Those who are unable to print the form off the website can order a copy to be sent to them by mail by calling the CRA’s individual income tax enquiries line at 1-800-959-8281. Detailed instructions on how to complete and submit a T1-ADJ E (23) can be found on page 2 of that form.
Taxpayers who are unsure of which method they may (or may not) be able to use to make a change on their return can find assistance through the “Confirm which option you can use” service on the CRA website. That feature, which is available on the CRA website at Changing a tax return – Personal income tax – Canada.ca as both a series of interactive questions and in a text document, will let the taxpayer know whether it’s possible to make the change online, or whether their request must be sent by mail.
No matter which method was originally used to file the return, or whether the correction is made online or in hard copy, there is one invariable rule. In all cases, it’s necessary to wait until the Notice of Assessment for the (incorrect) return already filed is received. Corrections to a return which are submitted prior to the time that return is assessed simply can’t be processed by the Agency.
Once the Notice of Assessment is received, and an adjustment request is made, it will take at least a few weeks before the CRA responds by issuing a Notice of Reassessment, based on the new information provided by the taxpayer. The current estimates for a response from the CRA are two weeks (for non-complex adjustment requests filed online) and up to 12 weeks for those submitted in hard copy. Not surprisingly, requests which are submitted during the CRA’s peak return processing period between March and July will likely take longer.
Sometimes the CRA will contact the taxpayer, even before a return is assessed (or reassessed), to request further information, clarification, or documentation of deductions or credits claimed (for example, receipts documenting medical expenses claimed, or childcare costs). Whatever the nature of the request, the best course of action is to respond promptly, and to provide the requested documents or information. The CRA can assess only on the basis of the information with which it is provided, and it is the taxpayer’s responsibility to provide support for any deduction or credit claims made. Where a request for information or supporting documentation for a claimed deduction or credit is ignored by the taxpayer, the assessment will proceed on the basis that such support does not exist. Providing the requested information or supporting documentation can usually resolve the question to the CRA’s satisfaction, and its assessment of the taxpayer’s return can then be completed.
If you would like help with dealing with the CRA or would like to know more about taxable benefits, please feel free to call us at (905) 305-9722 or email us at info@eigenmachtcrackower.com and we will help you out!
