T4, in plain English.

Check the actual T4 due date each year. The last-day-of-February rule moves to the next business day when CRA’s weekend or public-holiday rule applies.

Miss the T4 filing window and the Canada Revenue Agency has a formula for what comes next. For a payroll team carrying hundreds of employees through year-end, late T4 slips carry real weight.

What the T4 captures.

A T4, Statement of Remuneration Paid, reports the year’s remuneration and payroll deductions. CRA specifies when a slip is required. Separate slips can be needed for different provinces of employment or payroll accounts. CPP uses boxes 16 and 16A, QPP uses 17 and 17A, and QPIP premiums and insurable earnings use 55 and 56.

Both parties get a copy. The CRA uses it to verify what was remitted against the employer's reported totals. The employee relies on it to complete their annual return. When those copies tell the same story, the year is closed. When they do not, the CRA takes notice.

How the T4 is filed.

For 2025 remuneration, the T4 deadline was March 2, 2026. For 2026 remuneration, it is March 1, 2027 under CRA’s last-day-of-February and weekend/public-holiday rule. Employees receive their copies by the applicable deadline.

Employers submit the slips directly to the Canada Revenue Agency. Each slip reports the figures for its employee, province and payroll account. The CRA cross-references those figures against the remittances made throughout the year. A gap between what was withheld, what was remitted, and what the T4 shows is the kind of discrepancy that invites a review.

Mistakes that show up in audits.

• CPP and CPP2 reported as a single figure. The second additional CPP contribution is a separate amount from the base Canada Pension Plan contribution. Treating them as one combined total understates what was withheld in each category and produces a mismatch in CRA records.
• Amendments confused with later payments. Correct an erroneous filed T4 under CRA’s amendment rules. A new payment in a later year generally belongs in the year paid. It does not automatically amend the year the work was done.

What Workzoom calculates.

Workzoom has run Canadian payroll since 2001. Twenty-five years of CPP tables, EI rate changes, and year-end filing cycles. Family-owned, founder still leading it.

Workzoom calculates CPP, CPP2, EI premiums, and income tax on every pay run and generates T4 slips for the employer to submit and remit to the Canada Revenue Agency. No export step between systems. Because HR, time, and payroll share one database, the figures that populate the T4 are the same figures that drove every pay run across the year. No reconciliation between modules built separately and stitched together later.

County of Renfrew, an Ontario municipality, and Silvera for Seniors run Canadian payroll on Workzoom. For organizations where year-end accuracy is not optional, that single database is the whole point.