T4 Filing Deadline for Employers: Penalties and How to File

The T4 filing deadline for employers is the last day of February following the calendar year the pay relates to. For the 2026 tax year, February 28, 2027 falls on a Sunday, so slips and the T4 Summary are due Monday, March 1, 2027. Two obligations share that date: filing with CRA, and giving every employee their copy. Late filing costs $10 to $75 per day depending on slip count, with a minimum of $100 and a maximum of $7,500.

Anyone filing more than 5 slips has to file electronically. This guide covers who files, how to file, and what mistakes cost.

When Is the T4 Filing Deadline?

The deadline is tied to the end of February rather than a fixed date, so it shifts each year with the calendar. Slips covering wages paid during one calendar year are due by the last day of February in the year that follows. A weekend or a public holiday recognised by CRA pushes the due date forward, and a return counts as filed on time if it arrives by that next business day.

Two years are worth marking now. Pay earned in 2026 gets reported on slips due Monday, March 1, 2027, since February 28 that year is a Sunday. Pay earned in 2027 gets reported on slips due Tuesday, February 29, 2028, which is a leap day and a normal business day, so no extension applies. Employers who batch their year end work around a fixed calendar date get caught by exactly this kind of shift.

Two separate duties carry the same deadline, and missing either one triggers its own penalty. The first is the filing itself, meaning the slips plus the T4 Summary sent to CRA. The second is delivery to employees, which runs as two paper copies per person handed over or mailed to the last known address. Electronic delivery needs the employee’s consent first, in writing or recorded electronically, and an assumption does not count.

Who Has to File a T4 Slip?

Any employer who paid salary, wages, commissions, bonuses, vacation pay, tips, or taxable benefits files a T4. The threshold is low. A slip is required where you deducted CPP contributions, EI premiums, or income tax from any payment during 2026, or where the total paid to one employee passed $500 in the year.

Part year staff count the same as full year staff. An employee hired in October 2026 and let go in December still receives a slip by March 1, 2027, and so does a seasonal worker paid for six weeks in the summer. Directors of a corporation paid for their role receive slips too, even where the payment is a single annual amount. A dormant payroll account with no wages paid at all is the one case with nothing to file, though the account itself still needs closing or a nil remittance filed.

Contractors are the common mix up. A genuine contractor gets a T4A rather than a T4, and the distinction rests on control over the work, ownership of tools, and the chance of profit or loss, not on what the contract calls the person. Getting this wrong invites a CRA ruling that reclassifies the worker and assesses the missing CPP and EI. Our comparison of T4 vs T4A vs T5 slips explains which form reports what income, and employers who want the whole year end handled use payroll services in Toronto.

How to File T4 Slips With CRA?

Electronic filing is mandatory above 5 slips, and three routes exist.

1. CRA Web Forms

Web Forms is the free service built into the CRA website and suits employers with a handful of staff. You enter each slip by hand, and the system handles up to 100 slips per return, whether original, amended, additional, or cancelled. It validates entries as you type, calculates the Summary totals, and prints copies you can hand to employees.

Nothing gets installed and nothing gets purchased, which is why most small employers stop here. The trade off is speed. Manual entry for 40 employees takes an afternoon, and the session does not save partway through, so the data has to be ready before you start. Employers who file every year usually move to software once the headcount passes 20.

2. Internet File Transfer and Payroll Software

Internet file transfer accepts an XML file produced by payroll software, which suits employers running more than 100 slips or several payroll accounts at once. The software builds the slips, the Summary, and the T619 transmittal record together, then uploads the package in one submission and returns a confirmation number to keep on file.

One rule changed recently and still trips people up. Since January 2025, every return inside a single submission has to be the same information return type, so T4 and T4A returns go up separately rather than bundled together. Getting that wrong means a rejected submission days before the deadline. Our review of accounting software for small businesses covers the platforms that handle payroll and year end filing properly.

3. Paper Filing and Its Limits

Paper filing remains available only for 5 slips or fewer. File more than that on paper and CRA charges a separate penalty starting at $125 for 6 to 50 returns, rising to $2,500 at the top of the scale, and that penalty applies on top of any late filing charge.

The T4 Summary has to travel with paper slips, since CRA rejects slips arriving without one. Processing also takes considerably longer than an electronic submission, and no confirmation number exists to prove the filing date. Employers under the threshold can still file electronically, and in almost every case they should.

T4 Late Filing Penalties

The penalty depends on how many slips arrive late and how many days pass, calculated per type of information return rather than per individual slip.

Number of T4 Slips	Penalty Per Day	Maximum Penalty
1 to 50	$10	$1,000
51 to 500	$15	$1,500
501 to 2,500	$25	$2,500
2,501 to 10,000	$50	$5,000
10,001 or more	$75	$7,500

The minimum penalty is $100 in every case. An employer filing 10 slips 45 days late pays $450, since $10 per day beats the minimum. An employer with 80 slips filed the same 45 days late pays $675 at the $15 daily rate. The clock starts the day after the deadline, so a filing made on March 2, 2027 already carries one day of penalty.

Two more charges can land on the same year end. Filing T4 and T4A returns late brings two separate penalties, one for each return type, because CRA assesses per information return. Failure to give employees their copies on time carries its own penalty of $25 per day, with a $100 minimum and a $2,500 maximum, even where the CRA filing itself was on time. Interest runs on unpaid penalties, so the total keeps growing after the assessment arrives.

Common T4 Errors and the PIER Report

Box 14 causes the most trouble. Employment income has to include every taxable benefit, so a company vehicle, group life insurance premiums, and non cash gifts above the exempt limits all belong in that figure. Leave them out and the slip understates income while the deductions stay unchanged, which is exactly the mismatch CRA screens for.

That mismatch produces a PIER report, short for Pensionable and Insurable Earnings Review. CRA compares the CPP and EI you withheld against the pensionable and insurable earnings reported in Boxes 26 and 24, and any gap comes back as an assessment for the shortfall plus interest. Both the employee and employer portions fall on the employer, since you cannot recover the employee half from someone who left the company in August.

Three other boxes generate repeat errors. Box 10 needs the province of employment, which follows the establishment the employee reports to rather than where they live. Box 45 reports employer offered dental coverage and has been mandatory since the 2023 tax year. Boxes 16A and 17A capture second additional CPP contributions, which apply to earnings above the second ceiling. Our guide on payroll deductions in Canada shows which amounts feed which box, our list of payroll mistakes small businesses make covers the rest, and Alberta employers handle the work through payroll services in Calgary.

How to Fix a T4 After Filing?

Amended slips can be filed at any point after the original return, through the same electronic method or on paper. Mark the slip as amended, include only the slips that actually changed rather than resubmitting the whole batch, and send the employee a corrected copy. Cancelled slips follow the same process where a slip should never have been issued at all.

Correcting an error does not erase the penalty attached to the original shortfall. A CPP and EI gap discovered in June 2027 still carries the assessment tied to the March 1, 2027 filing, along with interest from that date. Amending early costs less than amending late, which is the argument for reconciling in January rather than waiting for CRA to raise it.

Larger problems deserve advice before anything gets filed. Several years of unreported taxable benefits, misclassified contractors, or missing slips for former employees are all situations where a correction made properly carries different consequences than one CRA uncovers on its own. Keep every slip and Summary for six years, which is also what you need on hand if a CRA review letter arrives.

File Early and Reconcile Before You Submit

The T4 filing deadline gives no grace period, and penalties begin the day after. March 1, 2027 is the date to work backward from for the 2026 tax year, and the reconciliation belongs in January rather than the final week of February.

Run three checks before anything gets transmitted. Match total remittances against the tax, CPP, and EI reported across all slips. Confirm every employee address and social insurance number. Add up the taxable benefits that belong in Box 14 but sit in a separate ledger. Those three steps prevent the PIER assessments that cost more than the filing penalty itself.

Tax Return Filers Professional Corporation prepares and files year end slips through payroll services in Brampton, so the figures reaching CRA agree with the remittances already sent. Ontario employers also review their Ontario employer health tax return at the same time, since that annual filing falls on March 15, two weeks after the T4 deadline.