Why Missing a Tax Deadline is Costly
Late tax payments trigger daily interest charges at CRA's prescribed rate (currently around 8% annually, compounded daily). Late filing also attracts penalties — up to 50% of unpaid tax for incorporated businesses. Working with a professional bookkeeping team ensures your records are accurate and deadline-ready throughout the year.
In Calgary, where many Calgary business owners operate with tight cash flow, even a week late can cost hundreds in interest. The solution: mark these dates on your calendar now and work with an accountant who keeps you on track.
2026 Key Tax Deadlines for Calgary Businesses
January Deadlines
- Jan 30, 2026 — T4 & T4A Summary due to CRA (from 2025 payroll)
- Jan 31, 2026 — T4s & T4As must be issued to employees & contractors
February Deadlines
- Feb 28, 2026 — Last day for employees to file 2025 personal tax returns (or Jun 15 if self-employed)
- Feb 28, 2026 — Information slips (T5, T3, etc.) due to CRA
March–May Deadlines
- Mar 15, 2026 — Q4 2025 installment payment due (if required)
- Apr 15, 2026 — Estimated 2026 Q1 installment due (if required)
- Apr 30, 2026 — Tax payment deadline for most individual filers
- May 15, 2026 — Estimated 2026 Q2 installment due
June Deadlines (CRITICAL)
- Jun 15, 2026 — Personal tax return deadline (self-employed, all individuals)
- Jun 30, 2026 — Corporate income tax return (T2) due for calendar-year corporations
- Jun 30, 2026 — GST/HST annual return due (calendar-year filers)
- Jun 30, 2026 — Partnership T1 General due
September–December Deadlines
- Sep 15, 2026 — Q3 2026 installment due
- Dec 15, 2026 — Q4 2026 installment due
- Dec 31, 2026 — Year-end for calendar-year corporations (plan tax strategies before this date)
Ongoing Monthly & Quarterly Deadlines
Payroll Remittances (Most Calgary Businesses)
- 15th of each month — CPP & EI deductions due to CRA (regular remitters)
- 15th of each month — Income tax withheld due to CRA
- Late payroll remittances trigger 3%–10% penalties plus interest
GST/HST Filing
- Quarterly filers: Due 1 month after quarter-end
- Monthly filers: Due within 1 month of month-end
- Annual filers: Due by June 30 (or month after year-end)
⚠️ Mark Your Calendar
The most commonly missed deadlines are payroll remittances (15th of month) and GST/HST filing. These attract immediate penalties. If you're unsure whether your current filing schedule is correct for your corporate year-end, speaking with a Calgary accountant can clarify your position quickly. Set up automatic reminders or work with an accountant who tracks these for you.
What If Your Alberta Business Has a Non-Calendar Fiscal Year?
If your business year-end is NOT December 31, your deadlines shift. For example:
- June 30 year-end corp → T2 due Dec 30
- August 31 year-end corp → T2 due Feb 28 (next year)
The rule: Corporate returns due 6 months after year-end. But tax payment is usually due 2–3 months after year-end. Check with your accountant for your specific dates.
Tax Planning Deadlines for Calgary Incorporated Businesses (Before Year-End)
The best tax strategies require action before December 31:
- Oct–Nov: Review current tax position. Plan RRSP & TFSA contributions.
- Nov–Dec: Implement dividend strategies, income splitting, or corporate restructuring.
- Dec 15: Last day for most RRSP/TFSA contributions to count for current year.
- Dec 31: Year-end — too late to implement strategies for current year.
Swift Accounting's Calendar-Based Service
We track these deadlines for every client. We'll remind you in advance, ensure filings are submitted on time, and keep your business compliant with CRA. Many Calgary business owners find it's worth reviewing their full compliance calendar with their accountant before year-end. We'll also identify opportunities to reduce your tax burden before year-end, not after.
Book a free consultation to put these deadlines in expert hands.