Canada Payroll — T4, Relevé 1, CNESST, WSIB and Source Deductions (Odoo Online)

What the paid edition adds

• Source deductions, from gross to net, pay period by pay period: CPP or QPP, CPP2 or QPP2, employment insurance at the federal or Quebec rate, QPIP, federal and provincial income tax. Each deduction shows the full detail of its calculation — what you present when the employee disputes it.

• The year-to-date total, which prevents contributions beyond the maximum. It is what payroll calculations most often get wrong, and it is what causes the overpayment discovered at year-end.

• The T4 and T4 Summary, with their deadline — the last day of February, moved to the next business day, and 30 days if the business ceases operations.

• Quebec's Relevé 1 (RL-1 slip), which parallels the T4 in Quebec.

• CNESST and WSIB: dated classification units, payroll capped per worker, premium calculated using the board's formula.

What the module refuses to do

• A T4 cannot be validated when an employee's contributions are inconsistent with their salary: a contribution above the annual maximum, or box 18 not matching box 24 at the year's rate. The refusal names the employee, the box and the variance in dollars.

• A T4 Summary cannot be validated while any slip is still in draft.

• An RL-1 slip (Relevé 1) is not produced for an employee whose pay for the year falls under a province other than Québec.

• A CNESST or WSIB premium cannot be calculated without a notified rate in force for the year, nor without a known maximum insurable earnings. An outdated rate is a missing rate.

• No withholding is calculated without a rate schedule in force on the payment date.

What is not shipped, and must be entered

These gaps are deliberate. Each was searched for in its primary source on September 14, 2026; none was filled with a plausible value.

• The federal basic personal amount. The Canada Revenue Agency refers to it as “BPAF”: since 2020 it varies with the employee's net income and does not exist as a single amount. Enter it based on the TD1 form. This is the first thing to do after installation — without it, no deduction can be calculated.

• CNESST and WSIB rates. They are specific to each classification unit and notified to the employer. The average rate published by the WSIB for 2026 is an average, not an applicable rate.

• The CNESST maximum yearly insurable earnings. The CNESST website blocks automated access; the value could not be confirmed. The rate table is marked “value not found” and the calculation is refused rather than rounded to zero.

• Quebec's tax tables. The Canada Revenue Agency does not publish the Quebec brackets: they are covered by Revenu Québec's guide TP-1015.G, to which automated access was refused. QPP (RRQ), QPIP (RQAP) and the 16.5% federal abatement are shipped; Quebec provincial income tax must be entered manually.

• The tax tables from January 1 to June 30, 2026. Only the 123rd edition of guide T4127, effective July 1, 2026, has been transcribed.

What the tax calculation does not do

The formula used is the basic form from the T4127 guide: tax = R × A − K − K1 − K2. The Ontario surtax is implemented. Not implemented: the other deductions in Chapter 2 of the T4127 — union dues, RRSP, alimony/support payments, northern residents deduction — as well as the Ontario tax reduction and the Ontario Health Premium. A low-income employee in Ontario will therefore pay a higher provincial tax here than in reality.

Provincial scope

• Deductions and tax: federal and Ontario brackets are shipped. Other provinces and territories are supported by the model but not shipped as data: their brackets must be entered, from the same table 8.1 of the T4127 guide. Québec, for its part, falls under Revenu Québec.

• Workplace accidents: Quebec (CNESST) and Ontario (WSIB), and only those. Each province has its own board — WorkSafeBC, WCB Alberta, WorkSafeNB and the others. None of them is covered.

Dependencies

hr and the free base module dyo_paie_canada. No dependency on ``hr_payroll``, which does not exist in Odoo Community.