Source deductions are the payroll amounts taken off employment pay before net pay is issued. In most Canada-first payroll questions, that means income tax withheld, CPP contributions, and EI premiums, plus the reporting and remittance logic tied to those deductions.
What Belongs Here
Use this subsection when the question is about what came off a paycheque before the employee received the net amount.
This is the right place for terms that answer questions such as:
- Why is net pay lower than gross pay?
- Which deduction is income tax, and which one is CPP or EI?
- How do source deductions later appear on a T4?
Best Starting Pages
Use these pages when the question is about what came off the paycheque rather than what happened after filing.
Practical Reader Path
This subsection usually answers one of two questions:
- what was withheld from pay
- how those withheld amounts show up later on a slip
If the question is no longer about the deduction itself, continue to Reporting and Remittance or Slips.
Use Nearby Sections When
- the issue is remittance timing, CRA due dates, or payroll account classification: go to Reporting and Remittance
- the issue is the year-end slip rather than the deduction itself: go to Slips
- the issue is the final personal-return result after payroll withholding: go to CRA Process and Compliance
In this section
- CPP Contribution
CPP contributions are payroll amounts withheld on pensionable earnings, matched by the employer, and remitted under CRA payroll rules.
- EI Premium
EI premiums are payroll amounts withheld on insurable earnings, with a related employer premium and separate CRA payroll reporting.
- Income Tax Withheld
Income tax withheld is the payroll tax deducted before net pay and later reconciled on the T1 return.
- Payroll Deduction
Payroll deductions are amounts taken from employment pay for income tax, CPP, EI, and related payroll obligations before net pay is issued.