T4 Box 42 — Employment commissions
Commission income portion of your Box 14 total — important if you want to claim commission-employee expenses on Form T2200/T777.
At a glance — Box 42
- Box name
- Employment commissions
- T1 line
- Line 10120 — Commissions (memo, not added on top of Line 10100)
- Check against
- Your commission statements or sales compensation records.
What Box 42 means
Box 42 shows the commission portion of your employment income separately from salary. It is already included in Box 14 — not on top of it.
Commission employees with a signed T2200 may deduct a broader range of employment expenses (advertising, client entertainment, home office, vehicle costs) than salaried employees.
Tax return implications
- Reported as memo on Line 10120 of the T1 (not added to Line 10100 — that would double-count).
- Qualifies you to use Form T777 with commission-employee rules if you have a T2200.
Related T4 boxes
Box 40 — Other taxable allowances and benefits
Total dollar value of non-cash taxable benefits your employer provided — company car, medical insurance, gift cards, stock options, etc. Already included in Box 14.
Box 44 — Union dues
Annual union or professional-association dues paid through payroll deduction — fully deductible from employment income.
Box 46 — Charitable donations
Charitable donations made through payroll deduction — claim them as part of your charitable donation tax credit.
Box 14 — Employment income
Your total gross employment income for the year before any deductions — salary, wages, bonuses, commissions, taxable benefits and most other pay.
Filing your return? Use the payroll deductions calculator to verify the amounts on your T4 match expected CPP, EI and income tax withholdings, and the income tax calculator to estimate your refund or balance owing.
Sources
T4 box definitions from CRA T4 employer guide. Rates and thresholds current for 2025; file your 2025 T1 by April 30, 2026 (self-employed June 15).