Ontario levies its own income tax on top of federal tax, with graduated provincial brackets, a basic personal amount credit, and a distinctive two-tier surtax that applies to net provincial tax above set thresholds. This free calculator reproduces the ON428 logic so you can estimate the provincial portion of your tax. Combine it with the federal calculator for your full Ontario tax bill.
How it works
- Tax income through Ontario’s graduated brackets (rates from 5.05% up to 13.16%).
- Subtract the basic personal amount credit (5.05% of the BPA) to get net provincial tax.
- Apply the Ontario surtax to that net tax: 20% on the amount above the first threshold, plus an additional 36% on the amount above the second threshold.
- Add the surtax back to net provincial tax for the total Ontario tax.
The surtax is what makes Ontario’s top marginal rate climb well above the headline 13.16% bracket.
Example
For a taxable income of $120,000, Ontario taxes the income through its brackets, subtracts the BPA credit, and — if the net provincial tax clears the first surtax threshold — adds 20% surtax on the excess. The result is the provincial tax; adding the federal figure gives the combined burden.
Notes
This is the provincial portion only and excludes federal tax, CPP and EI. The Ontario Health Premium and other credits can adjust the final number. Treat it as a planning estimate. Everything runs locally in your browser.