To amend a GST return after discovering an error, request an adjustment rather than filing another return for the same period. In My Business Account choose Adjust a return, or send a signed letter to your tax centre.
| Situation | What to do |
|---|---|
| Wrong amount on a filed return | Adjust a return in My Business Account, or a signed letter to your tax centre |
| Forgot an eligible ITC | Claim it on a later return within the ITC time limit — an adjustment is not always needed |
| Never filed the period | File the return now; penalties and interest may apply |
| Disagree with a CRA (re)assessment | File a notice of objection within the deadline, not an adjustment request |
| Error could draw a penalty | Consider the Voluntary Disclosures Program before CRA contacts you |
| Account administered by Revenu Québec | Use its amendment form (FPZ-2500-V, or FP-2500.E-V if the return included a schedule) |
First identify what needs changing
Find the RT account and reporting-period dates on the original return. Reconcile the relevant sales, GST/HST collected or collectible, eligible input tax credits (ITCs), and other entries against invoices and records. Work out the correct total for each affected line; for example, if line 101 was $5,000 but should have been $6,000, the corrected total is $6,000. A change may affect the net tax, interest or refund.
A forgotten eligible ITC may sometimes be claimed on a later return within its applicable time limit, so an adjustment is not always needed solely to claim that credit. For most registrants, CRA measures the four-year limit through the due date of the last return period ending within four years of the original period; a two-year limit applies to certain registrants. Check the business-use and documentation conditions and do not claim the same ITC twice. CRA: ITCs and time limits
How to amend a GST/HST return online
- Sign in to your CRA account and access My Business Account or Represent a Client.
- Choose GST/HST and the correct RT account, then select Adjust a return.
- Choose the reporting period from the list of periods eligible for electronic adjustment and make the changes using the corrected figures.
- Review and submit the request. Keep the confirmation and a copy of your supporting calculations, then monitor the account for CRA’s response. CRA: change a return
Amend a GST/HST return by letter
If electronic adjustment is unavailable or you choose the written route, send a letter to your tax centre, signed by the owner or an authorized representative. Include the business number and RT extension, the reporting period, corrected amounts for each affected line, and the name and telephone number of a contact. Keep a copy of the letter and the underlying records. CRA: adjustment information
What if the mistake means you owe more tax?
If the correction means you owe more tax, CRA charges interest on the shortfall from the day after it was originally due until it is paid, at the prescribed rate shown for late GST/HST amounts. If the error or omission could draw a penalty, consider contacting CRA’s Voluntary Disclosures Program (VDP) before CRA contacts you about it. An application is not voluntary if an audit or investigation has already been initiated, and if CRA grants relief, any tax owing must still be paid in full.
Missed return or disputed assessment?
If you forgot to file a GST/HST return, file the missing period now instead of requesting an adjustment — late-filing penalties and interest may apply; see also CRA’s time limits for reassessment. If you disagree with an assessment or reassessment, an adjustment request is different from a formal objection. The GST/HST objection deadline is generally 90 days after the notice was sent; asking for an adjustment does not replace that deadline. A personal income-tax T1 return has separate correction and objection rules. CRA: GST/HST objections
Do not assume an adjustment has the same processing time as an original return or that a refund is guaranteed. CRA says it normally processes an original GST/HST return, and issues the resulting refund, within 4 weeks of receiving it; an adjustment to an already-filed return is a separate request. Check your account, and contact CRA if you need information about an outstanding request. For accounts administered by Revenu Québec, use its FPZ-2500-V, Request to Amend a Return if the return did not include any schedules, or FP-2500.E-V if it did. CRA: after filing