Two Jobs Tax Calculator (Canada)

How the TD1 withholding mismatch works

1. 1

   Claim your basic personal amount once

   You complete a TD1 form for your main employer claiming the full federal and provincial basic personal amount.

2. 2

   Additional employers get $0 on Line 13

   Any other employer you work for at the same time receives a TD1 with $0 entered for the basic personal amount, checking the box for multiple employers.

3. 3

   Payroll deductions are calculated separately

   Each employer runs source deductions using only the income it pays you and the TD1 information you gave that specific employer.

4. 4

   CRA reconciles everything on your T1

   When you file your tax return, the CRA totals both incomes and applies the real federal and provincial brackets, comparing that to what was actually withheld.

The source-deduction mismatch formula

Mismatch = (Tax withheld on primary job + Tax withheld on secondary job) − Tax on (primary income + secondary income) combined

• •Only one employer applies your full basic personal amount at source.
• •Any other concurrent employer withholds tax without that credit, using $0 on Line 13 of its TD1.
• •CPP contributions and EI premiums are calculated separately by each employer and are not included here.
• •Provincial tax credits beyond the basic personal amount are also not modelled in this estimate.

Worked example

Someone earning C$80,000 from a main job and C$35,000 from a second job, with source deductions calculated separately by each employer.

Primary job income (annual)

C$80,000

Secondary job income (annual)

C$35,000

Total combined income

C$115,000

True combined tax (on total income)

$25,176.54

Total tax withheld (both jobs)

$21,281.07

Estimated tax bill (underpaid)

$3,895.47

In this example, the combined tax withheld across both jobs differs from the true tax owed on C$115,000 by $3,895.47.

Federal income tax brackets (2025)

These federal brackets apply to your true combined income once both jobs are added together on your tax return; provincial tax is calculated separately and added on top.

Source: Canada Revenue Agency (CRA)

Who this applies to

Anyone employed at two or more jobs at once

If you work concurrently for more than one employer during the same tax year, this TD1 mismatch can apply to you.

Employees who forgot to update their TD1

If you didn't check the multiple employers box or left the basic personal amount claimed at more than one job, the shortfall is usually larger.

Workers whose combined income crosses a tax bracket

The gap tends to be more noticeable when your combined income pushes you into a higher federal or provincial tax bracket than either job alone would suggest.

Not significant if your second job pays very little

If your total income from both jobs stays low, the missing basic personal amount at the second employer makes little practical difference.

Frequently Asked Questions

Why do I owe money at tax time even though both employers deducted tax?

Each employer only withholds tax based on the income it pays you and the TD1 you filed with it, so if you have more than one job at once, the combined amount withheld can be less than the real tax owed once the CRA adds both incomes together on your T1 return.

What should I put on the TD1 for my second job?

You should check the box indicating you have more than one employer and enter $0 on Line 13 for the basic personal amount, since that credit can only be claimed in full at the employer that pays you the highest income.

Does this include CPP and EI?

No, this estimate covers federal and provincial income tax only; Canada Pension Plan contributions and Employment Insurance premiums are calculated and deducted separately by each employer and are not part of this calculation.

Can I ask my employer to withhold extra tax instead of owing at filing time?

Yes, you can request that either employer deduct additional tax from each pay by submitting an updated TD1 or a letter requesting extra withholding, which reduces or eliminates the balance owing when you file your return.

Does my province affect the size of the mismatch?

Yes, because provincial tax brackets and rates vary and stack on top of federal tax, the exact size of the shortfall between combined withholding and real tax owed depends on which province or territory you live in.