Every working Canadian receives a T4 slip at tax time, yet most people glance at a few boxes and move on. Understanding what each box actually means — and knowing what to do when something looks off — can save you from filing errors, CRA correspondence, and missed deductions. This guide breaks down every significant box on your T4 and walks you through the steps to take when your slip is missing, late, or incorrect.
The T4 — officially called the Statement of Remuneration Paid — is the document your employer files with the Canada Revenue Agency and sends to you after each calendar year. It summarizes everything your employer paid you during that year: wages, salary, taxable benefits, and the deductions taken off your paycheques for income tax, Canada Pension Plan, and Employment Insurance.
Employers must file T4 slips and the accompanying T4 Summary with CRA by February 28 (or the next business day when February 28 falls on a weekend). You receive your copy at the same time. When you file your personal T1 return, you carry the figures from your T4 into the appropriate lines of your return. CRA cross-references its own copy, so mismatches trigger automatic notices.
This is the starting point for most filers. Box 14 reports your total gross employment income for the year: regular wages or salary, overtime, bonuses, commissions, and the value of most taxable benefits your employer provided. It is your income before any deductions for CPP, EI, or income tax. When you transfer this figure to your T1, it flows to Line 10100 (Employment income).
Box 16 shows how much you personally contributed to the Canada Pension Plan under the base CPP rate. For 2025, the maximum employee CPP contribution is $4,034.10. If you worked for more than one employer during the year, each employer deducts CPP independently, which can result in over-contributions. CRA automatically calculates any over-contribution and returns it as a refund or credit when you file.
Box 17 applies only to employees who worked in Quebec. The Quebec Pension Plan runs parallel to CPP but is administered by Revenu Québec rather than CRA. If you have employment income from both Quebec and another province in the same year, you may see amounts in both Box 16 and Box 17.
Box 18 records the Employment Insurance premiums your employer deducted from your pay. For 2025, the maximum employee EI premium is $1,077.48. Like CPP, if you had multiple employers, over-contributions are possible and are reconciled on your T1.
Box 22 is the total federal and provincial income tax your employer withheld from your paycheques throughout the year. This is the amount credited against your tax owing when CRA calculates your return. If Box 22 is lower than your actual tax liability — because of other income, extra RRSP room, or a change in circumstances — you will owe a balance. If it is higher, you receive a refund.
Box 24 may differ from Box 14. Not all income is insurable for EI purposes. Certain taxable benefits, pension income included in employment income, and amounts over the annual insurable earnings ceiling are excluded. EI premiums are calculated on Box 24, not Box 14, so the two figures often diverge.
Similar logic applies here. Box 26 reflects the portion of your earnings on which CPP or QPP contributions were actually calculated. It can differ from Box 14 because of the basic personal exemption applied to CPP and because some earnings types are non-pensionable.
If your employer provided a company vehicle for personal use, paid personal living expenses, or gave you other non-cash taxable benefits, the value appears in Box 40. A common example is the automobile standby charge — the CRA-calculated value of having a company car available for your personal use. This amount is also included in Box 14.
Union dues deducted from your pay are reported in Box 44. You claim this amount as a deduction on your T1 (Line 21200), reducing your net income. Keep your T4 and any union receipts to support the claim.
Some employers run payroll giving programs. Donations made through your employer appear in Box 46. You can claim these on Schedule 9 of your T1 for the charitable donations tax credit.
If your employer has a Registered Pension Plan or Deferred Profit Sharing Plan, Box 50 shows the CRA registration number for that plan. This number is for reference and does not directly affect your tax calculation, but it confirms that contributions to the plan are registered and therefore deductible or tax-sheltered.
The pension adjustment (PA) reflects the value of the benefit you accrued in your employer's registered pension plan during the year. CRA uses this figure to reduce your available RRSP contribution room for the following year. If your PA is $8,000, your RRSP room for the next year is reduced by $8,000 compared to what it would have been based on earned income alone.
Box 54 identifies your employer's CRA business number. If you ever need to contact CRA about employment income from a specific employer, or if you are filing a complaint about a missing T4, this number helps CRA locate the employer's account quickly.
CPP enhancement (the second additional CPP contribution, known as CPP2) was introduced to gradually increase retirement benefits. Box 55 shows your personal CPP2 contributions for the year. These are entered on a separate line of your T1 and generate a tax credit.
Box 56 is informational only. It shows the matching CPP2 amount your employer contributed on your behalf. You do not enter this amount anywhere on your T1; it is reported for transparency and record-keeping.
Employers are required to file both the individual T4 slips and the consolidated T4 Summary with CRA by February 28 each year (or the next business day). Employers who miss this deadline face a penalty of $25 per day, with a minimum penalty of $100 and a maximum of $2,500 per failure. Repeated or intentional late filing can attract additional scrutiny. For employees, this means your T4 should always be in hand — or visible in CRA My Account — before the end of February.
There are three common ways to receive your T4:
If February 28 passes and you have not received your T4, take these steps in order:
Errors on T4 slips are more common than most people expect — transposed digits, benefits included at the wrong value, or CPP/EI deducted on non-pensionable earnings. If you spot an error, your employer must issue an amended T4 with the corrected figures and file a corrected T4 Summary with CRA. Do not simply override the T4 figures on your return without an amended slip; CRA's system will flag the discrepancy.
Contact your payroll department in writing, describe the error clearly, and keep a copy of your correspondence. Once CRA receives the amended T4, the corrected figures flow through to your account automatically. If an employer refuses to issue a correction, CRA has authority to compel amendments.
If you changed jobs during the year, had a seasonal second job, or were employed by multiple employers simultaneously, you will receive a separate T4 from each employer. You report all of them on a single T1 return — add the Box 14 amounts from each slip together and carry the combined total to Line 10100. All CPP and EI amounts are also totalled across slips. As noted above, having multiple T4s increases the likelihood of CPP or EI over-contributions, which CRA reconciles automatically when your return is assessed.
At Swift Accounting Calgary, we regularly help employees and business owners review their T4s for accuracy, reconcile multi-employer situations, and ensure that taxable benefits, pension adjustments, and union dues are all handled correctly on the T1 return.
Box 14 is your total gross employment income including all taxable benefits. Box 24 is the portion of your earnings that is insurable for EI purposes. Some income types — such as certain taxable benefits, amounts above the annual EI insurable earnings maximum, and non-insurable earnings — are excluded from Box 24. Your EI premiums in Box 18 are calculated based on Box 24, not Box 14, which is why the two numbers often differ.
Technically, yes — CRA allows you to file using your final pay stub if your T4 has not arrived by the filing deadline. However, because CRA already has your T4 on file from your employer, any discrepancy between what you report and what CRA received will generate a reassessment notice. It is always better to wait for your T4 or retrieve it directly from CRA My Account after February 28.
Your RRSP contribution room for a given year is calculated as 18% of the previous year's earned income, up to the annual dollar limit. CRA then subtracts your pension adjustment from that calculation. A higher PA means less RRSP room, because CRA treats participation in a registered pension plan as a substitute for RRSP savings. The PA figure from Box 52 appears on your Notice of Assessment and is reflected in the RRSP room shown in your CRA My Account.
Even when an employer closes, they remain legally obligated to file T4 slips with CRA. If the business has been dissolved, contact CRA directly — CRA will have the T4 on file from the final payroll remittances. If CRA cannot locate a T4 for that employer, they will work with you to reconstruct the income based on payroll records, bank deposits, or Records of Employment. Swift Accounting can assist with this process and help you file accurately even in complicated employer situations.
If you have questions about your T4, need help reviewing multiple slips, or want to ensure your return reflects every deduction you are entitled to, our team is here to help. Contact Swift Accounting Calgary today to speak with an accountant who understands the full picture of your employment income.
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