If you earn income that isn't subject to automatic payroll withholding — whether from self-employment, rental properties, investments, or pension income — the CRA expects you to prepay your income tax throughout the year rather than settling the entire bill at filing time. These prepayments are called income tax instalments, and understanding how they work can save you from interest charges that compound daily.
Income tax instalments are quarterly prepayments of your personal or corporate income tax liability. Think of them as the self-employed or investment-income equivalent of the payroll deductions your employer automatically remits on your behalf. When you receive a paycheque, your employer calculates and sends your estimated income tax to the CRA before the money ever reaches your bank account. When you earn income outside of employment — or when your employment income doesn't fully cover your total tax owing — you're responsible for making those payments yourself, on a schedule set by the CRA.
The instalment system exists because the Canadian tax system is designed as a pay-as-you-go model. The government expects to receive tax revenue throughout the year, not as a single lump sum the following April or June. If you consistently owe a significant amount at tax time, the CRA requires you to spread those payments across the year.
The instalment requirement applies to you if your net tax owing exceeds $3,000 in the current tax year and in either of the two immediately preceding tax years. All three conditions don't need to be met simultaneously — the threshold triggers if the current year's net tax owing exceeds $3,000 and at least one of the prior two years also exceeded that amount.
Net tax owing means your federal and provincial income tax payable after credits, minus any income tax withheld at source by an employer or payer. This is the amount you still owe after all source deductions are accounted for.
The most common situations that create an instalment obligation include:
Quebec residents have a lower threshold: instalments are required when net tax owing exceeds $1,800 (combined federal and Quebec provincial), reflecting the province's separate tax administration.
For individuals, the CRA sets four quarterly instalment due dates each year. For 2025, those dates are:
Missing these dates — or underpaying — results in interest that begins accruing immediately from the due date. Payments must be received by the CRA by the due date, not merely postmarked, so build in extra time if you're mailing a cheque.
The CRA provides three accepted methods for calculating how much to pay each quarter. Choosing the right method depends on how predictable your income is and how much administrative effort you want to invest.
The prior-year method is the simplest and most widely used approach. You calculate one-quarter of your total net tax owing from the immediately preceding tax year and pay that amount at each of the four quarterly due dates.
For example, if your net tax owing for 2024 was $12,000, you would pay $3,000 at each of the four 2025 instalment dates.
The CRA's instalment reminder notices — sent in February for the March and June payments, and in August for the September and December payments — typically display the amounts calculated under this method. If you pay the amounts shown on the CRA's instalment reminders, you are fully protected from instalment interest and penalties, even if those amounts turn out to be less than your actual 2025 tax owing. This makes the prior-year method the safest choice for taxpayers whose income is relatively stable year over year.
The current-year method requires you to estimate your total net tax owing for the current year (2025) and pay one-quarter of that estimated amount at each quarterly due date.
This approach can result in lower payments if your income has dropped significantly compared to the prior year — useful if you've retired, reduced business activity, or experienced investment losses. However, it carries meaningful risk: if your actual 2025 income exceeds your estimate, you'll face interest on the shortfall from each due date. There is no safe-harbour protection when using the current-year method, which means an overly optimistic income estimate can be costly.
Taxpayers using this method should revisit their estimates regularly throughout the year and adjust upcoming payments if circumstances change.
The instalment base method — sometimes called the blended or no-calculation method — splits your payments between two reference years:
This method is particularly useful when the second-preceding year more accurately reflects your current income than the most recent filing year — for instance, if 2024 was an unusually high-income year due to a one-time event, but your 2023 and 2025 income are more typical.
Like the prior-year method, paying the amounts shown on the CRA's instalment reminders (which may reflect this blended calculation) provides interest protection.
The CRA charges interest on late or insufficient instalment payments at the prescribed interest rate plus 4 percentage points, compounded daily from the missed due date. With prescribed rates fluctuating and the additional surcharge, instalment interest can accumulate meaningfully over the course of a year.
Importantly, if you overpay one instalment, the excess can offset interest on a later underpayment — but only to a limited extent and only for the same tax year. The CRA calculates whether you owe instalment interest when it assesses your return.
One way to avoid instalment interest entirely is to pay the amounts printed on the CRA's February and August instalment reminder notices. Even if those amounts result in a balance owing at filing time, no instalment interest will be charged provided you paid in full on time each quarter.
The CRA offers several convenient payment options:
Always retain confirmation of payment. If you pay by cheque, keep a copy and track the cleared date to confirm CRA received it by the due date.
Instalment calculations become more complicated when income fluctuates significantly, when you have multiple income sources, or when you're navigating your first year of self-employment or retirement. Getting the amounts wrong in either direction — underpaying or tying up cash unnecessarily — has a real cost. The team at Swift Accounting Calgary works with business owners, investors, and retirees throughout the year to keep instalment obligations accurate, on time, and optimised for each client's cash flow situation.
Whether you've received your first CRA instalment reminder and aren't sure what to do, or you want a second opinion on your calculation method, contact Swift Accounting for a straightforward conversation about your specific situation.
The CRA will charge instalment interest at the prescribed rate plus 4%, compounded daily from the missed due date to the date payment is received. If the interest exceeds $1,000, the CRA may also assess an instalment penalty on top of the interest charge. There is no grace period — interest begins accruing the day after the due date.
Not necessarily. The $3,000 threshold is based on your net tax owing after accounting for all source deductions. If your employer withholds enough tax to bring your balance below $3,000 (in the current year and at least one of the two prior years), you are not required to make instalments. However, if you have significant additional income — from rental properties, investments, or a side business — your net tax owing after employment source deductions may still exceed the threshold.
You can use the current-year method to reduce or eliminate instalment payments if you expect your actual tax owing to be below $3,000. However, this is done at your own risk. If your income ends up higher than estimated, you'll owe interest on each underpaid quarterly amount from its original due date. If you do expect a refund because of new deductions or credits, document your reasoning carefully and reassess each quarter.
No. Canadian-controlled private corporations (CCPCs) and other corporations follow a separate instalment regime with monthly payments (not quarterly) and different thresholds and calculation rules under the Income Tax Act. Small CCPCs that meet certain criteria may qualify for quarterly corporate instalments. Corporate instalment obligations are separate from the personal instalments discussed here, and the rules can be more complex — particularly for associated corporations or those with fluctuating active business income.
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