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Tax Calendar · Canadian Compliance

How to Track Every CRA Deadline in 2026: T1, T2, GST, T3, T4, Payroll, WSIB & EHT

If your firm tracks deadlines in a spreadsheet, you've already been bitten — or you will be. Here's the complete 2026 CRA filing calendar every Canadian CPA firm needs, the eight filing types you can't miss, and the workflow that scales from 50 clients to 1,000.

By Gagan Kambo · May 3, 2026 · 11 min read

Short answer

A Canadian CPA firm needs to track eight filing categories with roughly fifteen distinct due-date rules across them. T1 is the loud one (April 30), but T2, T3, T4, GST/HST, Payroll, WSIB, and EHT each have their own frequency, year-end-relative deadlines, and penalty structures. Manually maintained spreadsheets break down past 50–80 clients. Auto-calculated deadlines tied to each client's year-end and filing type — refreshed continuously and surfaced on one dashboard — is the only system that scales without a missed return.

Why missed deadlines quietly kill firms

Every Canadian CPA firm's worst day starts the same way: a client phone call that begins, "I just got something from the CRA…" Late-filing penalties begin at 5% of the balance owing plus 1% per full month outstanding, capped at 12 months. Interest compounds daily at the CRA's prescribed rate. For a corporate client owing $30,000 of tax, missing the T2 deadline by six months turns into roughly $3,300 in penalties alone — not counting interest, the partner's hours making it right, and the trust the client lost.

And it's almost never the famous deadlines that bite. Firms don't miss April 30. They miss the GST/HST quarterly that was due in the middle of T1 season. They miss the T4 because a junior thought reception had it covered. They miss the WSIB filing for a client they assumed was "no payroll this quarter."

Here's a composite from interviews with Canadian practice owners: a 4-person firm in Brampton serving 220 clients lost two engagements in 2024 over missed T2 deadlines that landed during T1 crunch. Both clients were profitable corporate accounts. Both walked. The Excel tracker had been "fine" for years.

The 8 CRA filing types every Canadian CPA firm must track

This is the core canon. Every working day in your firm's calendar should be answerable against this list.

1. T1 — Personal Income Tax

2. T2 — Corporate Income Tax

3. T3 — Trust Income Tax

4. T4 / T4A — Information Slips

5. GST/HST

The most-missed filing type, and the worst one to miss because it directly hurts cash flow. Frequency is determined by annual taxable supplies:

Three different frequencies × different period-end-relative rules = a system that has to compute deadlines per-client, not per-calendar-date. Firms that maintain one master "GST due date" spreadsheet column inevitably miss returns for clients on a different frequency.

6. Payroll Remittance (PD7A)

Three frequencies set by the CRA based on average monthly withholding amount (AMWA):

7. WSIB (Ontario) and Provincial Workers' Comp

8. EHT (Employer Health Tax)

If your firm operates across provinces, you're tracking multiple EHT-equivalents simultaneously.

The 2026 deadline calendar at a glance

This is the public-facing calendar — the dates anchored to the year, not to a specific client's fiscal calendar. Use it as a forcing function for your monthly partner meeting:

Then add to that: every corporate client's T2 deadline (year-end + 6 months), every corporate client's T2 balance-due date (year-end + 2 or 3 months), every GST registrant's filing date (period end + 1 month for monthly/quarterly), and every payroll remittance for every employer. For a firm with 200 clients, that's well over 1,000 distinct deadlines per year.

5 ways firms quietly get this wrong

1. The "Master Spreadsheet" pattern

Every firm has had one: a tracker maintained by the bookkeeping lead, opened twice a week, color-coded. It works at 30 clients. It survives at 60. It silently fails at 100, when nobody can review every row weekly anymore.

2. Tracking the calendar date instead of the client's date

A firm puts "GST due — March 31" on the calendar. But that's only true for some clients. For monthly filers with February period-ends, the GST is due March 31 — but for a quarterly filer with a January 31 period end, it's due February 28. Calendar-based thinking misses the per-client variation.

3. Filing-only tracking, no balance-owing tracking

The classic T2 trap: the firm tracks "T2 due date" but not "balance owing date" (which is earlier). The return gets filed on time, but the balance was overdue four months. Interest accrues silently for an extra four months until the client gets the assessment notice.

4. Reminders that depend on humans remembering to look

"We send reminders 30 days before the deadline." Who sends them? When? What if that person is on vacation? What if a new client was onboarded last week and the reminder was never set up? Automated reminders only work if they're driven off the deadline, not driven off the staff.

5. No drift detection

Year-ends change. Corporate clients get bought and acquire new fiscal periods. Sole proprietors incorporate and now need T2s, not T1s. GST/HST frequency changes when the client crosses a threshold. Most firms don't have a process to catch these changes — so the deadline keeps firing on the old schedule for 18 months until somebody notices.

How to set up a deadline-tracking system that scales

Step 1: Capture the right inputs once, per client

For every client, your system needs: fiscal year-end, active filing types (T1? T2? GST? Payroll?), GST/HST frequency, payroll remittance frequency, and province (for provincial filings). Get this right at onboarding and the system computes everything else.

Step 2: Auto-calculate deadlines from year-ends

Don't store deadlines. Store the rule and let the system compute the deadline. T2 = year-end + 6 months. T2 balance owing = year-end + 2 months (or +3 for CCPC SBD). T3 = year-end + 90 days. The system is right by construction; nobody has to remember to update dates.

Step 3: Surface a unified deadline view

Every staff member should see one screen showing every filing for every client they touch — sortable by deadline date, filterable by filing type, with status badges (Not Started / In Progress / Filed). This is the difference between "We have a system" and "We have a list of systems nobody can see at once." Our dashboard and T1 tracker exist exactly for this.

Step 4: Automate reminders to clients and to staff

Two reminder channels matter: client reminders (we need your documents — 30/14/7 days out) and staff reminders (this filing is due in 5 days and not yet started). Both should fire automatically based on the deadline; never depend on someone to send them.

Step 5: Audit the system monthly

Once a month, run a 10-minute "what's coming up" report. Anything that's 30 days out and still "Not Started" is a flag. Anything that's 7 days out and "In Progress" is a partner-attention item. The audit is what turns a deadline-tracking system into a deadline-preventing system.

Why we built MyCPACRM around CRA deadlines

MyCPACRM was built by Canadian developers working with Canadian CPA firms. The tax filing module covers all eight filing types above out of the box: T1, T2, T3, T4/T4A, GST/HST (all four frequencies), Payroll Remittance (all three frequencies), WSIB, and EHT. Each filing's deadline is auto-calculated from the client's year-end and frequency configuration. The dashboard surfaces what's overdue, due this month, due next month, and coming up — for every client across the firm. Reminders fire automatically to clients and staff based on deadlines, customizable per filing type.

Spreadsheets gave Canadian CPA firms a way to track deadlines for two decades. It was always going to break at scale — and it did. The next generation of practice management is software that knows what a T2 is, what a CCPC is, what the 6-month rule is, what the 2-month rule is, and never confuses them.

Frequently Asked Questions

What is the T1 personal tax filing deadline in Canada for 2026?

April 30, 2026 for most individuals. Self-employed individuals (and their spouses) have until June 15, 2026 to file, but any tax owing must still be paid by April 30 to avoid interest charges.

When is the T2 corporate tax return due in Canada?

Six months after the corporation's fiscal year-end. A company with a December 31 year-end must file the T2 by June 30. Note that any tax balance owing is due earlier — generally two months after year-end (three months for a CCPC qualifying for the small business deduction).

How often must a Canadian business file GST/HST?

GST/HST filing frequency is set by the CRA based on annual taxable supplies: monthly (over $6M), quarterly ($1.5M to $6M), or annually (under $1.5M). Each frequency has a specific filing and payment deadline that depends on the reporting period end date.

What is the deadline for filing T4 slips?

T4 and T4A slips, plus the T4 Summary, must be filed with the CRA and distributed to recipients by February 28 (or February 29 in a leap year).

When is the T3 trust return due?

Within 90 days of the trust's year-end. Most trusts have a December 31 year-end, making March 31 the dominant T3 deadline.

How can a CPA firm track all client deadlines without missing any?

The most reliable approach is dedicated practice management software that auto-calculates each filing's due date from the client's year-end and filing type, then sends scheduled reminders and shows everything on a single dashboard. Spreadsheets work for under 30 clients but break down quickly past that.

What happens if a CPA firm misses a CRA filing deadline?

Late-filing penalties typically start at 5% of the balance owing plus 1% per full month, with a maximum of 12 months. Repeated late filing can trigger higher penalties (10% plus 2% per month, up to 20 months). Interest accrues daily on outstanding balances at the prescribed rate.

Stop tracking deadlines in Excel.

MyCPACRM tracks every CRA filing type for every client — auto-calculated, auto-reminded, all on one dashboard. Built by Canadians, for Canadian CPA firms.

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