How to Amend a GST/HST Return After Filing in Canada: The Key Rule
To amend a GST/HST return, do not submit a second return for the same period. Sign in to your CRA account, choose GST/HST, open Adjust a return, select an eligible reporting period and enter the corrections. If online adjustment is unavailable, CRA provides a signed-letter process.
Phoenix Knight Financial Services helps businesses in Surrey and across the Lower Mainland keep tax and accounting records clear. This article answers the specific filing question before showing where professional help may fit.
When Should You Amend a GST/HST Return?
You may need an adjustment if you entered the wrong sales amount, claimed input tax credits (ITCs) incorrectly, missed a taxable sale, or used the wrong tax figure. First compare the original filing against invoices, bank records and the ledger.
An amended GST/HST return fixes a return you already filed. It is not the same as filing a missing return. If you have not filed yet, follow the normal filing process rather than submitting an adjustment.
How to Change a GST/HST Return in Your CRA Account
- Sign in to the CRA account for the correct business.
- Open My Business Account or Represent a Client.
- Choose the GST/HST (RT) program account.
- Select Adjust a return.
- Choose the reporting period offered for electronic adjustment.
- Enter corrected amounts on the affected lines.
- Review the changes and keep the confirmation.
Only eligible periods appear in the online list. Do not try to fix a past mistake by filing another regular return for that same period.
What If You Cannot Adjust the Return Online?
CRA also allows a signed letter to the tax centre with the business number and RT extension, the reporting period, and corrected amounts for each affected GST/HST line. Include clear supporting details so the CRA can understand the adjustment.
If you are uncertain about a line number, review the official CRA return instructions before you send a request. An authorized representative may help prepare and submit the correction.
Common GST Return Errors and the Right Next Step
| Issue found | What to review before adjusting |
|---|---|
| Sales left out | Invoices, dates and sales tax collected |
| ITC claimed twice | Original receipts and expense ledger |
| Wrong reporting period | Invoice dates and period assigned by the CRA |
| Return filed twice | CRA account history; contact CRA before further action |
| Wrong GST/HST amount | Taxable supplies, rates and adjustments |
For BC businesses, be careful not to mix provincial PST figures into federal GST/HST return lines. Our GST/PST filing guide for BC explains the two systems.
What Happens After You Submit an Adjustment?
The CRA processes the change and may update the account balance, request documents or issue new correspondence. Check the status in your CRA account and save a copy of the revised figures.
An adjustment that increases the amount owing may also create interest charges. The time allowed for adjustments and claims can depend on the issue and reporting period, so older filings need extra care.
If your books do not match the filing, bookkeeping cleanup can help rebuild a clear trail. Related questions about overdue returns are covered in our guide to catching up on unfiled taxes.
How Can You Avoid GST/HST Filing Errors?
- Reconcile bank and credit card transactions before each GST/HST return.
- Separate taxable, zero-rated and exempt supplies correctly.
- Store invoices showing GST/HST paid on eligible expenses.
- Review the correct return period and accounting method.
- Have a second person check unusual entries before filing.
Accurate small business bookkeeping and a simple QuickBooks setup checklist can prevent many avoidable adjustments.
Frequently Asked Questions
Can I submit a second GST/HST return to fix the first one?
No. CRA says to adjust the previously filed return instead.
Where is the Adjust a return option?
In your CRA business or representative account under the relevant GST/HST RT account, for eligible periods.
Can I correct GST/HST by mail?
Yes. CRA provides a signed-letter adjustment process with required business and period details.
Will correcting a GST return cause a penalty?
An adjustment can change tax, interest or other amounts. The result depends on the facts and filing history.
What if my return has not been filed yet?
Prepare and file the original return instead of using the adjustment process.
Can an accountant help amend my GST return?
Yes. An authorized professional can review the ledger and prepare corrections.
Need help correcting a GST/HST return?
GoPK can help review your records, identify next steps and prepare for the relevant filing or bookkeeping requirement. Share the details of your situation so the right service can be discussed.
Official Guidance and Review Notes
Instructions follow the CRA adjustment steps. Some corrections require special care or further CRA review. Sources were checked for this article on October 21, 2026; tax obligations can depend on your specific facts.