How to Correct a Mistake on Your T4 Before Filing Your Taxes
A T4 slip summarises employment income and deductions reported to the Canada Revenue Agency (CRA). If the figures are wrong, filing with the original slip can lead to an incorrect refund, an unexpected balance, or a CRA review. Checking the document early gives your employer time to investigate and issue an amended version.
This guidance is especially useful for Canadians living in Australia, including people in Sydney, Melbourne, Brisbane, and Perth who still file a Canadian return. Australian workers usually deal with an income statement through myGov and the Australian Taxation Office, while a Canadian T4 relates to Canadian employment income and Canadian tax reporting.
Check Every Box Against Your Records
Compare your T4 with your final payslip, payroll portal, employment contract, and bank records. Review employment income in Box 14, income tax deducted in Box 22, and Canada Pension Plan and Employment Insurance amounts in Boxes 16 and 18. Also check taxable benefits, commissions, bonuses, and any pension adjustments.
Common errors include a missing bonus, duplicated employment income, an incorrect province of employment, or deductions that do not match your year-end payroll summary. A difference of a few dollars may be a rounding issue, but a substantial mismatch should be investigated before you submit your tax return.
Contact Payroll Before Filing
Your employer or payroll department is normally the first place to request a correction. Explain the problem clearly, attach supporting documents, and identify the tax year and the specific box that appears incorrect. Keep the request factual and retain a copy of your message.
If payroll agrees, it can issue an amended T4 and send the corrected information to the CRA. Ask when the revised slip will be available. Employers may need time to review historical payroll data, particularly when the mistake involves benefits, termination payments, or a business that has changed ownership.
Do Not Alter the Slip Yourself
Never cross out amounts, type over a PDF, or submit a self-edited T4 as though it were an official document. The CRA receives employer reporting separately, so figures on your return that do not match its records may trigger a review or delay.
Wait for the amended slip where possible. If the employer cannot be reached or refuses to correct an obvious error, collect your evidence and contact the CRA. A CRA representative can explain what documentation is acceptable and whether you should file using the available information.
Filing When the Correction Is Delayed
Tax filing deadlines can arrive before payroll resolves the mistake. If you must file, use the most accurate information supported by your records and keep detailed notes about the unresolved discrepancy. Do not knowingly claim an amount that is false simply because it appears on an incorrect slip.
You may later need to adjust the return after the amended T4 is issued. The CRA’s ReFILE service, an adjustment request through My Account, or Form T1-ADJ may be relevant depending on how the return was filed and the year involved. Follow the CRA’s instructions rather than sending multiple unrequested versions.
What Happens After an Amended T4
An amended T4 can change taxable income, payroll deductions, CPP contributions, EI premiums, credits, and benefits. The CRA may reassess your return automatically after receiving the revised slip, but you should still check your notice of assessment and compare it with the corrected figures.
A change in reported income can affect income-tested support. For example, rental income may influence eligibility for certain benefits, so Canadians reviewing broader household finances can read about GIS rental income when considering how a tax correction may affect government payments.
Special Issues for Australians Filing Canadian Returns
A Canadian citizen or resident living in Australia may have employment income, foreign tax obligations, and currency-conversion questions at the same time. A T4 should be reported in Canadian dollars using a reasonable, consistently applied exchange rate. Keep evidence of the rate and the date or method used.
Do not confuse a Canadian T4 with an Australian PAYG income statement. If you worked for an Australian employer in Melbourne or Sydney, that income is generally reported through the Australian tax system. If you worked remotely for a Canadian employer while living in Australia, residency, treaty, payroll withholding, and work-location rules can become important.
Canadian pension changes can also affect long-term planning for people abroad. Review the pension benefit update separately from employment-slip corrections, because CPP, OAS, and GIS rules are different from T4 reporting.
Keep a Clear Correction Record
Create a folder containing the original T4, amended T4, final payslips, payroll correspondence, CRA messages, and your calculation of the difference. Digital copies are useful for people moving between countries or managing records from different time zones.
Before filing, use this practical checklist:
- Compare every relevant T4 box with your final payslip and payroll records.
- Ask the employer for an amended slip in writing.
- Keep evidence if the correction is delayed or disputed.
- Check whether the change affects tax, credits, or income-tested benefits.
- Review your notice of assessment after the CRA processes the amendment.
| Situation | Sensible next step | Record to keep |
|---|---|---|
| Small payroll discrepancy | Ask payroll to verify the calculation | Payslip and written request |
| Missing bonus or benefit | Request an amended T4 | Bonus statement or benefits summary |
| Employer is unreachable | Contact the CRA with evidence | Employment records and contact attempts |
| Amended T4 arrives after filing | Request a reassessment or use the approved online option | Original and amended slips |
| Canadian filer living in Australia | Check Canadian and Australian reporting separately | Exchange-rate and residency records |
For general site limitations and financial-information boundaries, review the site disclaimer. Once the corrected figures are confirmed, file using the amended information, save your submission receipt, and monitor CRA correspondence until the matter is settled.