This is a lengthy read, not meant for skimming, but designed to serve as a complete resource for navigating Tax Installment Planning for 2026 in Canada. Apologies in advance for being long-winded.
Running a small service business in London, Ontario, the heart of the Forest City, means juggling clients, invoices, and cash flow. One often-overlooked area is tax installments to the Canada Revenue Agency (CRA). Paying taxes in advance through installments helps avoid big surprises (and penalties) at year-end. Proper tax installment planning keeps your business compliant and cash flow steady.
What Are Tax Installments?
Tax installments are advance payments of your corporation's income tax throughout the year. Instead of paying everything when you file your T2 return, the CRA requires spreading payments to match when income is earned.
This system treats corporations like employees who have taxes withheld from paycheques. For most corporations, installments cover federal and provincial (Ontario) corporate income tax.
Installments apply to taxes under Part I (general corporate income tax) and other parts, but not always to every credit or special tax. If your corporation owes little tax, you may skip them entirely.
Who Needs to Pay Tax Installments in Canada?
Not every corporation pays installments. Key rules for 2026:
You must pay if your tax payable (before certain credits) exceeds $3,000 in the current year or the previous year.
Exemptions include:
First tax year after incorporation (exceptions for some special taxes).
Tax payable of $3,000 or less in both current and prior years.
Most corporations pay monthly installments.
Eligible small Canadian-controlled private corporations (CCPCs) can pay quarterly if they meet criteria like taxable capital under $10 million, taxable income under $500,000, and good compliance history.
How Are Installment Amounts Calculated?
The CRA offers flexible ways to calculate installments. Corporations use worksheets like T2WS1, T2WS2 (monthly), or T2WS3 (quarterly) to figure amounts.
The three main options (similar to individual rules but adapted for corporations):
No-calculation method (often simplest): Pay amounts shown on CRA installment reminders (based on prior years). The CRA calculates using your latest assessed returns.
Prior-year option: Base installments on your previous year's (2025) tax payable. Divide by 12 (monthly) or 4 (quarterly).
Current-year estimate option: Use your best estimate of 2026 tax payable. This is ideal if income drops or you expect lower taxes (e.g., more deductions). Use CRA forms to estimate.
Many small service businesses choose the prior-year option for predictability or the current-year estimate if projecting lower profits. Overpaying gets refunded or credited; underpaying triggers interest.
Always review your Notice of Assessment from prior years for base amounts.
Payment Deadlines for 2026
Deadlines depend on your fiscal year-end and payment frequency.
Monthly installments (most corporations): Due on the last day of each month in your tax year. For a calendar-year business (Jan 1–Dec 31):
First: January 31, 2026
Then: Last day of February through December 2026
Quarterly installments (eligible CCPCs): Due one quarter less a day from fiscal year start. For calendar-year:
March 31, June 30, September 30, December 31, 2026 (adjusted if weekends/holidays).
The final balance of tax owing is due two months after fiscal year-end (three months for eligible CCPCs with small business deduction).
Late payments attract installment interest (compounded daily) and possible penalties if underpaid significantly.
Common Mistakes to Avoid
Small service businesses often trip on these:
Ignoring reminders: CRA sends notices; don't assume no notice means no payment.
Using the wrong calculation: Picking the no-calculation method when income drops leads to overpayment (refundable, but ties up cash).
Missing deadlines: Even one late monthly payment adds interest.
Forgetting provincial (Ontario) portion: Harmonized but tracked separately.
Not updating for changes: New revenue streams or expense increases affect estimates.
Tips for Better Tax Planning for Small Service Businesses
As a small service business in the Forest City, proactive income tax planning makes installments manageable:
Track quarterly: Review finances every three months. Use software like QuickBooks to project income/expenses.
Build a reserve: Set aside 20–30% of monthly revenue in a separate account for installments and balance owing.
Maximize deductions early: Claim home office, vehicle logs, supplies, and marketing costs to lower estimated tax.
Choose the best method: If expecting lower 2026 taxes (e.g., new hires or equipment purchases), use current-year estimate to reduce payments.
Pay electronically: Use CRA's My Business Account for easy, tracked payments.
Work with a pro: A trusted London CPA or accountant can run projections, choose optimal methods, and handle remittances.
Conclusion
Tax installment planning for 2026 keeps your Ontario small service business compliant and cash-flow healthy. Understand your obligations, pick the right calculation method, and stay on top of deadlines to avoid penalties.
If you're in London, Ontario, and need help with taxes, installments, or full-year planning, reach out to a local London CPA accountant for personalized advice. Proper setup now means smoother sailing all year.