The CRA “three-year rule” usually refers to the normal income-tax reassessment period for an individual or Canadian-controlled private corporation, generally measured from the earlier of the original assessment notice or notification that no tax is payable. GST/HST net-tax assessment has a separate general four-year rule measured from the later of the filing due date and actual filing date, subject to important exceptions. Neither rule is a three-year filing extension. Excise Tax Act, section 298. CRA income-tax reassessment guidance.
What Is the CRA 3-Year Rule? 3, 4, and 6 Years Compared
| Rule | Time Limit | Applies To |
|---|---|---|
| Normal reassessment period | 3 years | Income tax (individuals and CCPCs) |
| GST/HST net-tax assessment | Generally four years after the later of the due date and filing date | Section 298 has exceptions, including misrepresentation attributable to neglect, fraud and a valid waiver |
| Input Tax Credit claim window | Generally four years, with shorter periods for some registrants | GST/HST registrants (2 years for certain large businesses/financial institutions) |
| Record retention | 6 years | GST/HST records generally, with possible longer retention |
| Taxpayer relief for penalties and interest | Generally subject to a 10-year limit | Specific relief provisions, tax type and timing determine eligibility |
The 3-year figure people repeat online is real — it just belongs to income tax, not sales tax. GST/HST runs on its own, longer clock.
Does the CRA Give You 3 Years to File a GST/HST Return?
No. A GST/HST return is due on its applicable deadline, not three years after the period. Monthly and quarterly filers generally file and pay one month after period-end; most annual filers file and pay three months after fiscal year-end. An individual annual filer with a December 31 fiscal year-end and business income for income-tax purposes generally pays by April 30 and files by June 15. Check weekend and holiday adjustments. A return may still be required for a period with no sales; use the nil option only if all fields are zero. CRA reporting deadlines.
When Can the CRA Audit or Reassess You?
For a GST/HST net-tax assessment, the general limitation is four years after the later of the return’s due date and the date filed. Section 298 permits assessment outside the normal period in specified circumstances, including a misrepresentation attributable to neglect, carelessness or wilful default, fraud, or a valid waiver. Other assessment types have their own rules. An audit is not itself an assessment; do not assume an unfiled period is automatically time-barred. Excise Tax Act section 298.
How Long Must You Keep Records? (The 6-Year Rule)
Keep GST/HST records generally for six years from the end of the year they relate to. CRA can require a longer period, and early destruction requires written permission. CRA record-retention guidance.
How to File an Overdue or Current Return
Most registrants must file GST/HST returns electronically; charities, selected listed financial institutions and approved case-by-case exemptions have different rules. CRA My Business Account does not require a separate GST/HST access code; the standalone NETFILE form does. Save the six-digit confirmation number for a successfully submitted NETFILE return. CRA filing requirements.
Quick Answers
Can the CRA audit me after three years? Audit powers and assessment limits are different. The ordinary GST/HST net-tax assessment rule is generally four years from the later of the due date and filing date, with statutory exceptions; check the particular situation.
Do I have three years to file back taxes? No. File by the applicable due date. Interest and penalties depend on the return, balance owing and other conditions.
How many years of GST/HST records should I keep? Generally six years from the end of the year to which they relate. CRA may require longer retention; early destruction requires written permission.
This is general information, not legal or accounting advice. Confirm your specific filing and reassessment dates through CRA My Business Account, or with a professional, before relying on them.
Related guides
Sources
- Government: section 298
- CRA: reassessment a return income
- CRA: gst hst records keep
- CRA: reporting requirements and deadlines
Sources checked October 17, 2026.