Tax Instalments 2026: Calculator, Threshold and Due Dates in Quebec

Anyone whose estimated net tax owing for the year is more than $1,800 and was also more than $1,800 in either of the two previous years. Revenu Québec applies that threshold, and the Canada Revenue Agency applies the same $1,800 threshold to a Quebec resident ($3,000 elsewhere in Canada). The two tests are separate: you may owe instalments to only one of the two governments.

March 15, June 15, September 15 and December 15, federally and in Quebec. The CRA treats a payment as on time if it is received on the next business day when the due date falls on a Saturday, a Sunday or a public holiday, as March 15, 2026 did, a Sunday. Farmers and fishers make a single payment instead, by December 31.

There are three. Pay the amounts on the reminders the CRA (INNS1) and Revenu Québec (TPZ-1026.A) send you: paid on time, they protect you from interest even if they turn out too low. Split the previous year's net tax owing into four. Or split your estimate for the current year into four, useful when your income drops, but you pay interest if the estimate is too low.

Revenu Québec charges interest compounded daily on any missing payment, plus additional interest of 10% a year if you paid less than 75% of what you owed. The CRA charges interest at the prescribed rate, compounded daily, when it comes to more than $25, and a penalty when that interest is more than $1,000 for the year. Paying early or paying more than required reduces that interest.

Quebec income tax and, where applicable, your contributions to the Québec Pension Plan, the Health Services Fund, the prescription drug insurance plan and the Québec Parental Insurance Plan. Net tax owing is the year's tax minus the tax withheld at source and refundable tax credits. GST and QST instalments of a registered business follow other rules.