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The Income Tax Act is the federal law that decides who pays income tax in Canada, what counts as income and which deductions and credits apply. The official version was last amended on June 18, 2026, and most people only ever deal with Part I.
What does the Income Tax Act cover?
It’s a long statute with its own numbered parts. It explains how you work out income from a job, a business, property and capital gains before it gets to what you can subtract and which credits reduce your tax. It also holds the rules for registered plans such as the RRSP and the TFSA, along with the powers the Canada Revenue Agency uses to collect. The Department of Justice’s Income Tax Act page describes it as setting out the rules for determining income, calculating taxable income and tax, and handling returns, assessments, payments and appeals.
Provinces and territories add their own tax on top of the federal amount, and each sets its own rates. Quebec residents also file a separate provincial return. Your total bill is federal tax plus provincial tax.
Plenty of money rules live elsewhere. CPP contributions come from the Canada Pension Plan, EI premiums from the Employment Insurance Act and GST/HST from the Excise Tax Act, so a payslip draws on several laws at once.
Which parts will you actually meet?
| Part | What it deals with |
|---|---|
| Part I | Income tax on individuals and corporations |
| Part I.01 | Stock option benefit deferral tax |
| Part I.1 | Individual surtax |
| Part I.2 | Tax on Old Age Security benefits |
| Part I.3 | Tax on large corporations |
| Later parts | Special taxes, non-residents, transfer pricing and enforcement |
Inside Part I the sections follow the order of a return: income, deductions, taxable income, tax rates, credits. If someone quotes you a section number, look it up on the Justice Laws website, which keeps the current text. Don’t expect it to read like a magazine article. Sections refer to other sections, and a definition can sit pages away from the rule that uses it.
How does the Act turn into a tax bill?
The Act sets the method, and the government adjusts the dollar figures for inflation each year. For 2026 the federal rates are 14% up to $58,523, 20.5% to $117,045, 26% to $181,440, 29% to $258,482 and 33% above that. Only the slice of income inside each band is taxed at that band’s rate.
Take a worker in Ontario with $75,000 of employment income. The income tax calculator gives taxable income of $74,273 after the CPP and EI credits, federal tax of $8,258.60 and Ontario tax of $4,446.06. That’s $12,704.65 of income tax in total, an average rate of 16.9%. Ask the marginal tax rate calculator about the next dollar of work income and it says 28.5% in Ontario. So the taxman takes about 17 cents of each dollar on average, but nearly 29 cents of the next one.
Capital gains come under the same Act. A $95,000 gain in Ontario adds $47,500 to income, since half of a gain is taxable, and costs $17,450.83 in extra tax. Want to try other sale prices? The capital gains tax calculator does that.
What’s the difference between a credit and a deduction?
A deduction lowers the income that gets taxed, so it saves tax at your top rate. A credit comes off the tax itself, and the federal credit rate is 14% of the amount. The tax credits calculator shows what an RRSP contribution or another claim saves you. The basic personal amount can be as high as $16,452 at lower incomes, and it falls for very high earners.
Say a $1,000 deduction and a $1,000 credit land on the same return. At the federal 20.5% bracket the deduction saves $205 of federal tax, while the credit saves $140. Same number on the slip, different result, which is why the label matters.
Where do people get this wrong?
- They read a summary as if it were the law. Guides, this one included, simplify, and the statute and the CRA’s own pages decide.
- They use last year’s brackets. The dollar amounts change every January.
- They assume provincial rates match the federal ones. Each province sets its own.
- They expect the calculators to model every claim. Ours count the basic personal amount, the employment amount and the CPP and EI credits, but not benefits or rare credits.
- They take this page for legal advice. A complex case needs a tax professional.
Where these figures come from
The structure of the Act is taken from the Department of Justice Laws website, current to September 2026. Federal brackets and the personal amount come from Canada Revenue Agency pages for 2026, checked on September 29, 2026. Examples were produced by the calculators on this site. No government body is connected to this website.
Frequently asked questions
What is the Income Tax Act?
The federal law that sets who pays income tax, what counts as income, and which deductions and credits apply.
Where can I read the Act itself?
The Department of Justice publishes the current text on its Justice Laws website, with a note of the latest amendment.
Does the Act set provincial tax rates?
No. Each province and territory sets its own rates and adds its tax to the federal amount. Quebec residents also file a provincial return.
What are the 2026 federal tax rates?
14%, 20.5%, 26%, 29% and 33%, with the first band ending at $58,523.
Is a plain guide enough to file my return?
For a simple return often yes, but the statute and CRA pages decide. Complex cases need a professional.
- How Canadian income tax works: brackets and credits
How federal and provincial Canadian income tax stack up, what marginal and average rates mean, and how credits and deductions change your bill