What is a T1 Adjustment & How Do I Submit One?

If you have a reason to make changes to your income tax and benefit return filed for a particular tax year, you do not have to refile your taxes all over again.

Instead, you can use a T1 adjustment form to request changes to your filed tax return.

What is a T1 adjustment?

A T1 adjustment is a form that you can use to make changes to your income tax return.

Generally, you are expected to wait for a tax assessment from the Canada Revenue Agency (CRA) before sending in a T1 adjustment request form.

The CRA allows you to change your return for a tax year as far back as ten calendar years.

How to Change Your Tax Return (T1-ADJ)

There are three primary ways to change your tax return using the T1 adjustment form.

You can make adjustments through your CRA account, the ReFILE online platform, or by mail.

1. CRA My Account

Through your CRA My Account profile, the Change my return (CMR) service provides a secure way for you to make changes to your tax return.

Using the ‘change my return’ platform, you can only make adjustments relating to your marital status, address, direct deposit, and email address.

According to the CRA, you cannot make adjustments if:

  • a tax assessment has not been received for the tax return, 
  • nine reassessments have been done for the tax return in a particular tax year,
  • it is a bankruptcy tax return or one before the year of bankruptcy,
  • it relates to carryback amounts, elected split-pension, or international or non-resident clients,
  • it is a return that includes income from a business that has a permanent establishment outside your province or territory of residence,
  • it is a return that the CRA filed under subsection 152(7).

For these types of requests, you may need to send a request via mail—this is discussed below.

2. ReFILE

If you have filed your tax and benefit rerun electronically, you can use ReFILE to make T1 tax adjustments.

As an individual, you can request an adjustment to your T1 return for tax years from 2017 to 2020 using the certified NETFILE software, while an EFILE service provider can request changes using the EFILE accredited software.

When using the T1 adjustment form to request tax return adjustments, you are not required to submit supporting documents.

However, it is recommended to keep these documents in case the CRA requests them. 

The ReFILE is a quick and easy way to get your tax return reassessment, and there are situations that you may not be able to use the Refile services.

The CRA lists such cases here.

You can only make nine adjustments per tax year using the online system to make tax and benefit return adjustments.

Additionally, you cannot make changes to your personal information using ReFILE.

3. Mail

If you need to request a tax return change by mail, you must fill out the T1 adjustment paper form and send it along with supporting documents to the CRA.

You will have to send a separate mail for tax return adjustments as you cannot send this together with the tax return for the current tax year. 

Did You Know?

If you make a mistake on your tax return or have additional information to report, you can make adjustment requests to the CRA

What is the Mailing Address for a T1 Adjustment Form?

The mailing address for a T1 adjustment form is the same address you would use to send your income tax and benefit return for the applicable tax year.

The CRA has specified different addresses that apply to residents in various provinces and countries here.

How Long Will it Take to Process My Tax Adjustment?

While the CRA suggests a T1 reassessment timeline of two weeks to eight weeks, the actual time it takes to complete the tax reassessment may vary depending on the particular situation or reason for an adjustment request.

Adjustment requests that are considered to be complex may take a longer time to process.

Frequently Asked Questions

  • How do I submit a T1 adjustment?
  • How far back can you amend a T1?

Adeola is a Chartered Accountant and business finance professional. She is very passionate about financial literacy and education. When she’s not crunching numbers, she loves spending time with family.