Tax season can be a stressful time for many individuals and business owners. Filing your tax return accurately is crucial to avoid penalties and maximize your tax savings. However, mistakes can happen, and it's important to know how to fix a mistake on your tax return. In this article, we will walk you through the process of fixing errors on your Canadian tax return and provide a brief preview of common mistakes when filing your income tax returns.

Common Mistakes on Tax Returns

Here are some of the most common mistakes people make on their Canadian tax returns:

  • Forgetting to Claim Deductions or Credits

One common mistake is forgetting to claim all eligible deductions and credits. It can be challenging to keep track of the numerous tax deductions and credits available, especially with changing tax rules. To avoid missing out on potential tax savings, consider consulting with a professional tax accountant who can help identify applicable deductions and credits. Utilizing tax software can also assist in identifying eligible deductions and credits.

  • Failure to Transfer Unused Tax Credits

Tax credits can often be transferred to a spouse who may have insufficient income or taxes to utilize them fully. For example, unused tuition tax credits can be transferred to a parent or grandparent. Maximizing available tax credits can result in significant tax savings for families. Consulting with a tax professional can help navigate the intricacies of transferring unused tax credits.

  • Claiming Ineligible Expenses

On the flip side, some individuals mistakenly claim deductions or tax credits that are not allowed. It's crucial to understand the eligibility criteria for each deduction and credit before claiming them. For example, the Home Accessibility Tax Credit is only available for individuals who have made eligible renovations to improve accessibility in their homes.

Similarly, the deduction for student loan interest is often mistakenly claimed. Some students claim the student loan interest tax credit for payments made on personal loans, student credit, or foreign student loans, even though these expenses are not eligible. Hence, familiarize yourself with the requirements for each deduction and credit to ensure you are claiming them correctly. Ensuring accuracy and compliance with tax regulations is essential to avoid potential penalties and CRA audit triggers.

  • Inaccurate Reporting of Marital Status

Accurately reporting your marital status is crucial for determining eligibility for certain benefits and credits. If you're living with your partner in a conjugal relationship for at least 12 consecutive months or are sharing a child, you're considered common-law for tax purposes. Its important to report your marital status correctly as your marital status directly affects the benefits and credits you may be entitled to. The Canada Revenue Agency (CRA) calculates benefits such as the Canada Child Benefits, GST/HST credit, and the Working Income Tax Benefit based on your combined family income.

Reporting incorrect marital status can potentially result in the repayment of benefits received. To learn more about marital status changes, read our blog article "Importance of Informing CRA of Marital Status Change".

  • Missing the Tax Filing Deadline

Missing the tax filing deadline can have various consequences, including delayed refunds, late penalties, and interest charges. It's crucial to be aware of the deadline specific to your situation. For employed individuals, the deadline is typically April 30th, while self-employed individuals have until June 15th to file their taxes. To ensure you don't miss any 2024 tax deadlines, be sure to read our article on the various deadlines for individuals and businesses.

  • Not Filing Electronically

If you have never submitted your taxes electronically, you are overlooking numerous advantages. Firstly, it is significantly quicker and simpler compared to filing on paper. Importantly, it also offers greater accuracy. The CRA handles electronic filings with much greater speed and efficiency than paper ones, reducing the likelihood of errors that could potentially delay your refund.

How to Fix a Mistake on Your Tax Return in Canada?

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When it comes to correcting errors on your Canadian tax return, there are several methods you can use. Let's explore the different ways to request changes:

1. Online via CRA MyAccount

If you filed your tax return electronically using NETFILE or EFILE, you can make changes through the CRA MyAccount portal. Logging into your account and selecting the "Change my return" option allows you to enter the necessary adjustments. The online tool allows you to select the tax year you wish to modify and input the line numbers and corresponding figures to rectify or include information.

You cannot use the "Change my return" feature to request changes for the following:

  • Tax returns that have not been assessed yet
  • Tax returns that have been reassessed 8 times in the same tax year
  • Bankruptcy returns
  • Returns filed prior to a bankruptcy return
  • Returns filed for international or non-resident clients, even if they are considered Canadian Residents, newcomers to Canada, or individuals who left Canada during the year

You must request a change of return by mail for any of the above situations.

2. ReFile

ReFile is a service available to taxpayers who filed their returns electronically through certified software. It allows for changes to assessed returns within the last four years. However, there are exceptions to the eligibility for using ReFile. Detailed information about ReFile can be found on the CRA's website.

3. Mail

For those who prefer traditional methods, requesting changes by mail is an option. Fill out Form T1-ADJ, T1 Adjustment Request, and mail it to your local tax center. Ensure that you include copies of all supporting documents, such as receipts and slips, related to the adjustments being made. The processing time for mail-in adjustments is typically longer than online requests, ranging from several weeks to a couple of months.

The CRA Voluntary Disclosure Program (VDP)

In situations where errors or omissions on your tax return may result in penalties, the CRA has established the Voluntary Disclosure Program (VDP). This program allows taxpayers to rectify mistakes made on previously filed returns or file overdue returns without facing penalties or prosecution.

To be eligible for the Voluntary Disclosure Program, certain criteria must be met. The CRA under the new Voluntary Disclosure Program sets out the following five conditions

  1. The disclosure must be voluntary, meaning that the CRA should have no prior knowledge of the tax issue being disclosed.
  2. The disclosure must be complete, including all relevant information for the tax years affected by the error or omission.
  3. The taxpayer must owe taxes as a result of inaccurate or missing tax filings. The VDP does not apply to situations where a taxpayer is eligible for tax refunds.
  4. The tax returns being disclosed must be at least one year past the filing due date, unless part of a broader disclosure for older years.
  5. The taxpayer is required to estimate and pay the tax owing upfront as part of the disclosure process.

If you are uncertain about whether this program is suitable for you, NBG Chartered Professional Accountants can provide guidance on submitting your application under the CRA's voluntary disclosure program.


In conclusion, while errors on tax returns can be stressful, the Canadian tax system provides avenues for correction. Whether it's through online tools, mail-in requests, or the CRA's Voluntary Disclosure Program, taxpayers have opportunities to rectify mistakes and ensure compliance. By understanding common errors, seeking professional assistance when needed, and staying informed, you can navigate the tax filing process with confidence and peace of mind.

If you are looking for an accountant in Hamilton for professional guidance on filing your tax returns and ensuring that you are properly claiming all deductions and credits you are entitled to, contact us today. We are a full-service accounting firm in Hamilton that have experienced tax accountants to handle all your tax needs.

If you want to learn more about other tax and accounting topics, explore the rest of our blog!


The information provided on this page is intended to provide general information. The information does not take into account your personal situation and is not intended to be used without consultation from accounting/tax professionals. NBG Chartered Professional Accountant Professional Corporation will not be held liable for any problems that arise from the usage of the information provided on this page.

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Written by Neena Gambhir

I'm a Chartered Professional Accountant and have been navigating the waters of public accounting for over a decade. I've had the privilege to work with all sorts of clients – from small family-owned businesses to those big names on the stock exchange, spanning various sectors. Through these experiences, I've gathered a ton of knowledge, especially when it comes to Canadian corporate and individual taxes. I've also got a solid handle on the ins and outs of partnership, trust, and estate taxes.

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