T4 filing timeline for employers

What the T4 filing timeline means and why it matters

The phrase T4 filing timeline refers to the sequence of employer tasks and official deadlines that govern year-end payroll reporting in Canada: reconciling payroll records, preparing T4 slips for employees, issuing those slips to employees, and filing the T4 Summary and information returns with the Canada Revenue Agency. Every employer who pays salary, wages, taxable benefits, or other remuneration to employees must follow this timeline so employees can file their personal returns and the employer remains compliant with CRA reporting rules. For the CRA's official explanation of when information returns are due, consult the CRA guidance on when to file information returns.

Core T4 filing timeline: the employer's year-end sequence

The following ordered timeline describes the practical steps most employers follow each year. Each task is paired with its purpose and the CRA reference you should consult before you act.

1. Close and reconcile payroll for the calendar year

• Confirm gross pay, taxable benefits, CPP, EI, and income tax withholdings for each employee.
• Reconcile payroll remittances against payroll registers and your CRA remittance statements, and correct any posting errors before producing slips.
• This step reduces the risk of mismatches between remitted amounts and amounts reported on T4 slips, and it simplifies year-end adjustments. See the CRA Employers' Guide RC4120 for details about payroll items that must appear on T4 slips.

2. Prepare T4 slips and the T4 Summary

Generate a T4 slip for each employee who received salary, wages, taxable allowances, or taxable benefits in the calendar year. At the same time, prepare the T4 Summary that aggregates totals for all slips. Use payroll software or approved CRA-certified transmitters so your electronic files match CRA formats when you file. Consult the CRA Employers' Guide RC4120 and the CRA overview on tax slips for technical instructions on completing and filing T4 slips and the T4 Summary.

3. Issue T4 slips to employees

• Provide each employee with their T4 slip by the CRA deadline so they can file their personal income tax return on time.
• The standard practice is to deliver slips in a timely manner once reconciliations are complete. Refer to the CRA guidance on obtaining copies of tax slips for information about how slips must be issued to employees.

4. File T4 slips and the T4 Summary with CRA

File information returns with the CRA by the official deadline stated in CRA guidance. Many employers file electronically using certified software or CRA transmitters, while small filers with limited slips may still use paper where permitted. Always check the CRA "When to file information returns" guidance for current deadlines and accepted filing methods before submitting your returns.

How to file T4 slips and the T4 Summary with CRA

The CRA accepts information returns through several routes. Most medium and large employers must file electronically. Smaller employers may be eligible to file paper returns in limited circumstances, but electronic filing is increasingly the norm. Before you begin electronic transmission, review the CRA guidance on filing information returns electronically to learn about supported file formats, compatible software, and preparatory steps.

Common electronic filing options

• Payroll or accounting software that is CRA-certified, then transmit via the software provider's approved channel.
• Third-party payroll processors and transmitters who submit returns on your behalf using a secure CRA-approved gateway.
• CRA business portals or web forms, if available for your account and slip volume.

If you plan to file electronically, start the setup early so you can confirm transmitter credentials, test file formats, and register any new software accounts well before the filing deadline. The CRA electronic filing guidance explains required steps and recommended testing procedures.

Common T4 mistakes and simple payroll controls

Errors at year end create stress for employers and employees and may require amended slips. The most frequent issues and the controls that prevent them include the items below.

Frequent errors

• Missing or incorrect Social Insurance Numbers, names, or addresses on slips.
• Miscalculated taxable benefits or employer-paid amounts not reported as benefits.
• Payroll remittances that do not match reported CPP, EI, or income tax withholdings.
• Blending pay periods across calendar years without correct year-to-date values.

Simple payroll controls

• Perform regular payroll reconciliations each pay run and a dedicated year-end reconciliation before producing slips.
• Require employees to confirm SIN and personal details annually, and validate SIN entries against payroll records.
• Use payroll software that enforces data validation and produces CRA-compatible T4 files.
• Keep detailed records of taxable benefits and employer contributions with supporting documentation to justify year-end values.

Implementing these controls reduces corrections and makes electronic filing smoother. The CRA Employers' Guide RC4120 provides additional technical examples and reporting rules.

If you miss the deadline or must correct a T4 slip

If you discover a late or incorrect T4, act promptly. File the correct or amended slip with CRA as soon as possible and issue corrected slips to affected employees. Notify your payroll and accounting teams so remittances and records can be reconciled. Consult the CRA guidance on when to file information returns and the Employers' Guide RC4120 for the correct amendment process and next steps for reporting. Avoid guessing about penalties, and consult CRA pages directly if you need precise penalty or interest information.

Deciding whether to file yourself or hire professional payroll help

Choose professional help when your internal capacity, payroll complexity, or risk tolerance makes accurate year-end reporting difficult. Use these decision criteria to decide if external payroll support is appropriate.

Decision criteria

• Number of employees and the volume of T4 slips you will issue.
• Complexity of taxable benefits, pensionable earnings, or multiple payroll streams.
• Whether you already use cloud-based accounting or payroll software and need integration with CRA electronic filing.
• Internal staff time available for reconciliations and year-end adjustments.
• Your appetite for audit readiness and accurate documentation if CRA requests verification.

Modern payroll firms use secure cloud systems that offer real-time access to records and audit-ready reporting. Verma Accounting & Financial Services provides payroll processing, T4 preparation, and electronic filing support, and offers remote, cloud-based delivery plus a free consultation to assess your needs. If you already work with an accountant or want hands-on support through year end, a professional can handle transmitter setup, validate file formats, and take responsibility for timely filing. For related personal return questions that employees may have, see Verma Accounting's personal tax services.

Quick 30-day checklist and next steps for Ontario employers

Use this short checklist to move from payroll close to T4-ready status within 30 days. Each task is practical and measurable.

• Day 1 to 7: Run a full payroll register for the year, extract year-to-date totals, and list employees with missing SINs or contact details.
• Day 8 to 14: Reconcile CPP, EI, and income tax remittances to payroll totals, flag discrepancies for correction.
• Day 15 to 20: Generate draft T4 slips and review taxable benefits, pensionable earnings, and employer contributions line by line.
• Day 21 to 25: Validate employee addresses and delivery preferences, and prepare to issue slips to employees.
• Day 26 to 30: File T4 slips and the T4 Summary with CRA electronically or by the method you confirmed, then confirm receipt and store filed copies in a secure, audit-ready location.

For CRA filing step-by-step requirements and technical file preparation, consult the CRA guidance on filing information returns electronically and the Employers' Guide RC4120 before you submit files.