How this calculator works
Every T4 slip carries two numbers that matter here: box 14, your employment income for the year, and box 22, the income tax your employer already deducted and sent to CRA on your behalf. This calculator adds up box 14 across every T4 you enter, subtracts your RRSP contribution, and runs the result through the identical federal-and-provincial tax engine as our Take-Home Pay Calculator — CRA's T4127 annual method, and Revenu Québec's TP-1015.F-V formula in Quebec — to work out your true tax for the year. Subtracting the box 22 amounts you actually had withheld from that true tax gives the gap: a refund if you had more withheld than you owe, a balance owing if you had less.
Refund (or balance owing) = Tax already deducted at source − True tax
Why withholding and your final tax bill are different numbers
Nothing goes wrong when the box 22 total doesn't match your final bill — it's built into how payroll withholding works. CRA's annualized method has your employer take each pay period's amount, project it out as though every remaining period looked the same, and withhold tax on that annualized figure — a clean approximation, not a real-time tax return. It has no way to see an RRSP contribution you make on your own outside payroll, since the deduction only exists once you claim it on your return. It also can't see credits that never touch a TD1 form — donations, eligible medical expenses, tuition — because the TD1 only covers a short, fixed list of personal amounts. And if you start the year at one salary and get a raise, bonus or new job partway through, each period's annualized estimate is only ever a snapshot of the pay rate at that moment, not the year as a whole. None of this is a mistake by your employer; it's simply a different, narrower calculation than the one CRA runs when you file.
If you have a second T4
Add your other employer's income and tax deducted in the optional fields and this calculator combines both T4s into one true-tax calculation, the same way CRA does when it processes your return. Two T4s usually make the gap bigger, not smaller: each employer withholds as though its own paycheque were your entire income for the year, so neither one taxes your combined earnings at the higher bracket they actually land in once added together. Our Two Jobs Tax Calculator is built specifically around that bracket-stacking effect and is worth a look if two T4s are your normal situation, not a one-off. There's an offsetting effect in the other direction, too: CPP (or QPP in Quebec) and EI (or QPIP) each stop at a fixed annual ceiling, and every employer applies that ceiling only to what it pays you. Two incomes that individually stay under the ceiling can, once combined, sail past it — meaning you can contribute more than the true annual maximum even though both employers followed the rules correctly. CRA refunds that excess automatically at lines 44800 and 45000 (Quebec residents recover the QPP and QPIP portions through their Quebec return instead — CRA's line 44800 doesn't apply to them); this calculator estimates it separately and adds a note when it applies, since it's easy to miss and it works in your favour.
A refund isn't a bonus
It's tempting to treat a refund as a windfall, but it's really the return of money that was always yours — an interest-free loan you gave the government for up to a year, while it could have been sitting in your own account, paying down a balance or earning interest instead. A small refund, or a small balance owing, means your withholding tracked your real tax bill closely all year; either extreme means it didn't. The two mechanisms for reducing withholding are an updated TD1 that claims every personal credit you're entitled to, and — for deductions the TD1 can't list, such as RRSP contributions — a T1213 letter of authority from CRA that instructs your employer directly.
Worked example — a refund
Employment income $65,000, a $3,000 RRSP contribution, $9,600 already deducted at source (T4 box 22), Ontario — this calculator's own defaults, with a box 22 figure entered.
- Taxable income: $65,000 − $3,000 RRSP − $615 enhanced CPP deduction = $61,385.00.
- True tax: federal $5,691.99 + Ontario $3,144.01 = $8,836.00.
- Tax already deducted: $9,600.00.
- Refund: $764.00 — the RRSP deduction saved more tax than the box 22 withholding assumed, since payroll withholding on a $65,000 salary with no RRSP deduction on file would normally land closer to $9,725.50.
Worked example — a balance owing
Same $65,000 income and province, no RRSP contribution this time, and $8,000 withheld at source — a plausible T4 box 22 figure if a raise or bonus landed only partway through the year.
- True tax: federal $6,306.99 + Ontario $3,418.51 = $9,725.50 — this also happens to be what a standard employer withholding estimate on $65,000 with no RRSP produces, since there's no RRSP deduction here to create a gap on its own.
- Tax already deducted: $8,000.00 — less than the true tax, because the $8,000 reflects real per-period withholding rather than this calculator's clean annual estimate.
- Balance owing: $1,725.50.
Worked example — two T4s
The same $70,000-plus-$30,000 Ontario pair already verified in our Two Jobs Tax Calculator, entered here as two T4s with no RRSP contribution and each employer's own default (standalone) withholding estimate left in place.
- Total income: $100,000.00. Taxable income: $98,873.00 (after the enhanced CPP deduction on the combined income).
- Tax deducted at source: $11,133.91 (Job 1) + $2,452.11 (Job 2) = $13,586.02.
- True tax on the combined $100,000: federal $13,301.60 + Ontario $6,722.75 = $20,024.35.
- Balance owing before any CPP/EI credit: $6,438.32.
- CPP and EI overpayment: $887.05 of CPP plus $489.00 of EI, refunded automatically — $1,376.05 — bringing the real balance owing to roughly $5,062.27 once that credit is applied.
This worked example deliberately uses each employer's own standalone withholding estimate (what CRA's method produces assuming that job is your only income) rather than a real T4 box 22 figure — enter your actual figures for your own two T4s. If your second employer withheld at TD1 claim code 0, as the form directs once your personal credits are already claimed with another employer, its real box 22 is higher than this default and the gap correspondingly smaller.
When to file your 2026 tax return
Following the CRA's usual rule, the deadline to file a 2026 personal tax return and pay any balance owing is April 30, 2027. If you or your spouse or common-law partner were self-employed at any point in 2026, the filing deadline extends to June 15, 2027 — but the payment deadline does not move: any amount owing is still due April 30, 2027, and CRA's compound daily interest starts the day after, even on a return filed under the extension. When a due date falls on a weekend or a public holiday CRA recognizes, the CRA treats a return or payment as on time if it's received, or postmarked, by the next business day — but that rule doesn't apply this cycle, since April 30, 2027 is a Friday and June 15, 2027 is a Tuesday. CRA republishes its own deadline page for each filing season, so it's worth a quick check on canada.ca once the filing season for 2026 returns opens in early 2027, in case anything changes between now and then.
FAQ
How does this calculator estimate my refund or balance owing?
It runs your total 2026 employment income — everything you enter across one or two T4s — through the same federal-and-provincial tax engine as our Take-Home Pay Calculator, using CRA's T4127 annual method (Revenu Québec's TP-1015.F-V in Quebec) after subtracting your RRSP contribution. That's your true tax for the year. Subtract the tax already deducted at source (the box 22 amounts on your T4 slips — plus Relevé 1 box E in Quebec, where provincial tax is withheld and filed separately) from that true tax: a positive difference is a balance owing, a negative one is a refund.
Why doesn't the tax deducted on my T4 match my final tax bill?
Your employer's payroll system withholds tax using CRA's own annualized method — it takes each paycheque, assumes the whole year looks the same, and withholds accordingly. That estimate can't see an RRSP contribution you make outside payroll, credits that aren't on your TD1 (donations, medical expenses, tuition), or a second job. Any of those change your true tax without changing what was withheld, which is exactly the gap this calculator estimates.
What happens if I have more than one T4?
Add your second employer's income and tax deducted in the optional fields. Two T4 jobs almost always widen the gap: each employer withholds as though its own paycheque were your only income, so your combined income gets taxed at a higher rate than either employer applied on its own — a bracket-stacking effect our Two Jobs Tax Calculator covers in depth. Working the other way, each employer also applies the annual CPP/QPP and EI/QPIP ceilings independently, so two incomes can together overpay those contributions even though neither employer did anything wrong; it's refunded automatically when you file (Quebec residents recover the QPP and QPIP portions on their Quebec return), and this calculator flags it separately from the income-tax figure above.
Is getting a big refund actually good news?
A refund is the return of money that was already yours: tax withheld during the year beyond what you owed, held by CRA without interest until you filed. It isn't a bonus, and a small refund or a small balance owing means your withholding tracked your real tax closely all year. Withholding can be reduced through an updated TD1 that claims every personal credit you're entitled to, or, for deductions the TD1 can't list such as RRSP contributions, a T1213 letter of authority from CRA — whether either is worth doing depends on circumstances this page can't see.
When do I need to file my 2026 tax return?
Following CRA's usual rule, most individuals will have until April 30, 2027 to file their 2026 return and pay any balance owing. If you or your spouse or common-law partner were self-employed in 2026, the filing deadline moves to June 15, 2027 — but any amount owing is still due April 30, 2027, to avoid interest. Both 2027 dates land on a weekday (a Friday and a Tuesday), so CRA's usual next-business-day extension for a deadline that falls on a weekend or holiday doesn't come into play this cycle. Confirm the exact date on canada.ca closer to filing season, since CRA updates its own deadline page each year.
What doesn't this calculator account for?
It only models T4 employment income, tax already withheld, and an RRSP deduction — not eligible medical expenses, charitable donations, tuition, capital gains or losses, self-employment income, or any credit beyond the basic personal amount that the shared tax engine already applies. Every one of those either adds to a refund or reduces a balance owing beyond what's shown here, so treat this as a floor on your likely refund (or a ceiling on your likely balance owing), not a final number. It also doesn't check whether an RRSP contribution is within your deduction room — use the RRSP Refund Calculator for that.
This page is general information based on published 2026 federal and provincial payroll formulas and CRA's own filing-deadline guidance, not tax or financial advice. Your Notice of Assessment is the real number, and your actual return may differ — talk to a licensed accountant about your specific situation.