Quebec IT contractors and consultants do not deal with a single quarterly instalment system. They deal with two separate tax authorities running in parallel.
Quarterly instalments are prepayments toward the year’s eventual tax liability, not a separate tax.
Federal instalments go to the Canada Revenue Agency. Provincial instalments go to Revenu Québec. Both follow the same quarterly due dates, but the calculations, notices, and interest assessments are separate. A contractor who makes all of their federal instalment payments on time but misses the Quebec payments will still face interest from Revenu Québec on each missed due date.
Incorporation does not eliminate personal instalments. Contractors drawing salary, taxable dividends, or retaining insufficient source deductions can still trigger personal quarterly instalment obligations alongside separate corporate instalments.
This guide covers how the two-track system works and what it means for incorporated IT contractors and self-employed consultants operating in Quebec. The mechanics of federal instalments are covered in the quarterly tax instalments guide. Read that first if the instalment requirement itself is new.
The Quebec threshold is lower
Federal instalments are generally required when net tax owing exceeds CAD $3,000 in the current year and in either of the two preceding years.
Quebec’s threshold is CAD $1,800.
A contractor whose Quebec net tax owing crosses $1,800 is required to make Quebec provincial instalments even if their federal net tax owing stays below $3,000 and no federal instalments are required. The two thresholds operate independently.
For Quebec instalment purposes, the calculation includes Quebec income tax payable and certain contributions collected through the TP-1 return, including QPP contributions on self-employment income. It does not include QST, which has its own filing and remittance schedule through Revenu Québec.
Two parallel tracks
| Federal | Quebec | |
|---|---|---|
| Administered by | CRA | Revenu Québec |
| Threshold | CAD $3,000 | CAD $1,800 |
| Due dates | March 15, June 15, September 15, December 15 | March 15, June 15, September 15, December 15 |
| Remittance form | Federal payment (INNS3 or My Account) | TP-1066-V |
| Instalment protection method | Pay CRA’s reminder amounts on time | Pay RQ’s reminder amounts on time |
| Interest for shortfall | CRA prescribed rate, compounded daily | RQ prescribed rate, compounded daily |
Both tracks share the same quarterly due dates, but they require two separate payments to two separate agencies. Paying CRA does not satisfy Revenu Québec.
Why the amounts differ
Quebec residents pay less federal tax than residents of other provinces with equivalent income. The federal Quebec abatement reduces federal income tax by 16.5% for full-year Quebec residents. This reduction exists because Quebec levies its own provincial income tax separately from the federal system and funds its own programs that are otherwise covered federally elsewhere.
The effect on instalments is direct. CRA’s instalment reminders sent to Quebec residents reflect the abatement: the federal amounts are lower than what would appear on a comparable Ontario return. Revenu Québec sends its own instalment notices with amounts based on Quebec tax at Quebec rates.
The combined total of federal and Quebec provincial instalments across four quarters represents the contractor’s estimated full-year tax obligation. Neither agency sends a combined notice. A contractor who only follows CRA’s reminders is monitoring only one side of the obligation.
Revenu Québec instalment reminders
Revenu Québec sends instalment notices in February and August, similar to CRA’s schedule. The February notice covers the first two quarters (March 15 and June 15). The August notice covers the third and fourth quarters (September 15 and December 15).
The amounts on the notices are calculated based on the prior-year Quebec return. If you pay exactly what Revenu Québec requests, on time, you are generally protected from instalment interest even if the amounts undershoot your actual current-year Quebec liability.
If you do not receive a notice, or if your income has changed significantly from the prior year, you have the same calculation options that apply federally: the no-calculation method (pay what RQ requests), the prior-year method (base payments on prior-year Quebec liability), or the current-year method (estimate current-year Quebec tax and pay accordingly). The current-year method carries the same risk as it does federally: underestimating your Quebec tax triggers interest from each missed due date.
TP-1066: making the Quebec payment
Quebec instalment payments are made using Form TP-1066-V, titled Advance Payment of Income Tax.
Revenu Québec refers to these payments as advance payments in some forms and publications. Form TP-1066-V is the remittance form used to make Quebec personal income tax instalment payments.
Payments can be made through Revenu Québec’s online services, through financial institutions participating in Revenu Québec’s payment system, or by cheque with the TP-1066 remittance slip. Online payment through Mon dossier pour les citoyens generally provides the clearest confirmation of payment receipt and timing.
The payment date that matters is when Revenu Québec receives the payment, not when it is initiated. Initiating a payment through an online banking system one day before the due date may not result in same-day receipt by Revenu Québec. Building in one to two business days of lead time reduces the risk of a late payment being assessed interest.
Two-track interest risk
CRA and Revenu Québec each charge interest on missed or underpaid instalments starting from the relevant due date. The rates are set independently and change each quarter.
If a contractor makes their federal instalments on time but misses their Quebec instalments, Revenu Québec interest accrues from each missed due date. The reverse is equally true. Each agency administers and assesses its own instalment obligation independently.
Interest on late Quebec instalments is not deductible for income tax purposes, consistent with the federal treatment of instalment interest.
Revenu Québec can also assess an instalment penalty when instalment interest exceeds prescribed thresholds, similar in concept to the federal instalment penalty regime. Interest and penalties from both agencies are separate and can apply simultaneously.
Incorporated contractors: corporate versus personal
The above covers the personal income tax instalment obligation on the TP-1 return.
Incorporated IT contractors also have corporate tax at both the federal and Quebec level. Corporate tax instalments follow a different schedule. Federal corporate instalments are generally due monthly, although certain CCPCs may qualify for quarterly instalments if specific conditions are met. Quebec corporate income tax instalments are administered separately by Revenu Québec alongside the CO-17 corporate filing system. Corporate instalments are separate from the personal TP-1 instalments described in this guide.
For an incorporated contractor who draws salary from the corporation, the salary creates a personal TP-1 instalment obligation if the resulting personal tax owing crosses the $1,800 threshold. Contractors compensated primarily through dividends often face higher personal instalment exposure because dividend payments do not automatically include withholding tax the way payroll salary does. Contractors paying themselves through payroll with sufficient source deductions may reduce or eliminate the need for personal instalments entirely, depending on the level of tax withheld during the year. The corporation simultaneously has its own instalment obligation on retained corporate income. Both obligations require separate tracking, notices, and payment monitoring.
See tax filing for IT contractors with a Quebec establishment for how the corporate and personal filing structures interact.
QPP on self-employment income
Self-employed individuals in Quebec pay QPP contributions on net self-employment income. These contributions are included in the instalment calculation used to determine whether the $1,800 Quebec threshold has been crossed. If QPP contributions push the total above $1,800, the instalment requirement applies even if Quebec income tax alone would not have crossed the threshold.
QPP contributions are calculated and reported on the TP-1 return. For self-employed contractors, QPP instalment amounts should be factored into the quarterly payment estimate alongside Quebec income tax. Revenu Québec’s instalment notices incorporate QPP into the amounts, but only if the prior year’s return reflects self-employment QPP.
Practical considerations
Quebec contractors tracking both instalment obligations simultaneously need two sets of reminder notices, two payment records, and two confirmed payment receipts per quarter.
Quarterly tax exposure arises when income tax is not fully covered through withholding at source. Contractors transitioning from employment to self-employment or corporation-based compensation structures are often surprised because prior payroll withholding no longer offsets quarterly tax exposure automatically.
The February notices from both CRA and Revenu Québec should arrive within a few weeks of each other. If one does not arrive, contact the relevant agency before the March 15 due date. Missing a notice does not suspend the instalment obligation.
Setting aside a combined percentage of net income that accounts for both federal and Quebec provincial tax reduces the cash flow pressure at each due date. Quebec’s combined federal and provincial personal income tax rates are among the higher rates in Canada at upper income levels. Contractors who recently moved to Quebec can encounter instalment mismatches because prior-year CRA and Revenu Québec calculations may have been based on different provinces or residency periods.
Instalment planning is most straightforward when it is built into the year-round income and cash flow picture. For IT contractors operating in Quebec, particularly those with variable income or who are in their first year of Quebec residency, working with a CPA who can estimate the two-track obligation and select the right calculation method for each agency can help reduce both interest exposure and unnecessary overpayment risk.