Resources
Official pages, checked and dated
The CRA and the Ontario government own these rules. These are direct links to the pages that state them, grouped by what you are trying to do.
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Calculators
Work it out first
Eighteen calculators built on the rates these pages publish.
Tax and CRA deadlines
The dates and thresholds the CRA sets, worked out for your situation.
Browse026 calculatorsRunning a business
Everyday arithmetic for owners — pricing, break-even, and what to put aside.
Browse034 calculatorsPersonal tax and savings
Estimates for your own return, your pay, and your registered accounts.
Browse043 calculatorsGeneral money tools
Plain arithmetic that applies whoever you are and wherever you bank.
BrowseThe official sources
Grouped by need
Every link was checked on September 2026. Rules change — the official page is the authority, not a summary of it.
If you run a business
- When to register for and start charging the GST/HSTThe $30,000 small supplier threshold, effective registration dates, and the 29-day rule.
- When to file your corporation income tax returnThe six-month rule, with CRA's own worked examples.
- Remit payroll deductions — when to remit and due datesDue dates for each remitter type, and the withholding amounts that set them.
- Employers' Guide — Payroll Deductions and Remittances (T4001)The full CRA guide for employers, updated annually.
- Important dates for corporationsInstalments, balance-due day and the filing calendar in one place.
If you are filing a personal return
- Filing due dates for the 2025 tax returnApril 30 for most people, June 15 if you or your spouse are self-employed.
- Due dates and payment dates — personal income taxFiling and payment dates, instalments, and benefit payment dates.
- Sign in to your CRA accountWhere to find slips you have lost and check your notice of assessment.
- Rental income (T4036)CRA's guide to reporting rental income and expenses.
- Line 32300 — Tuition, education and textbook amountsHow tuition credits work, including carry-forward and transfers.
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