How to Calculate Corporate Tax in Canada: Step-by-Step With Examples (2026)

To calculate corporate tax in Canada, take your corporation’s taxable income, apply the federal rate (9% on the first $500,000 if you qualify for the small business deduction, 15% on the rest), then add your province’s rate on the same income. For a small Ontario corporation, that works out to roughly 11% to 12% combined. For an Alberta corporation, it’s 11%.

That’s the whole formula. The rest of this guide walks through each piece so you can build your own corporate tax calculator in a spreadsheet, or sanity-check the result from any online Canada corporate tax calculator.

How Corporate Tax Is Calculated in Canada (Federal + Provincial)

Every Canadian corporation pays two layers of tax on the same income: federal and provincial (or territorial). You work out each layer separately, then add them together.

Step 1: Start with taxable income. This is not the same as the profit on your income statement. Taxable income is your accounting profit after adjustments, like capital cost allowance instead of accounting depreciation, and only 50% of meals and entertainment. If you’re unsure, your accountant’s adjusted figure is the one to use.

Step 2: Work out how much qualifies for the small business rate. Only active business income earned by a Canadian-controlled private corporation (CCPC) qualifies, up to the business limit. The federal limit is $500,000.

Step 3: Apply the federal rate. 9% on income that qualifies, 15% on everything else.

Step 4: Apply your provincial rate. Each province has its own small business rate and general rate. Add the provincial tax to the federal tax and you have your total.

Here are the 2026 combined rates for the three provinces most Bizincs clients ask about:

Province	Small business (combined)	General (combined)
Ontario	11.2% from July 1, 2026 (12.2% before)	26.5%
Alberta	11%	23%
British Columbia	11%	27%

One catch for Ontario. The province cut its small business rate from 3.2% to 2.2% effective July 1, 2026, and it’s prorated by days if your tax year straddles that date. A calendar-year 2026 corporation lands at about 2.7% provincial, so around 11.7% combined. A tax year that starts on or after July 1, 2026 gets the full 2.2%.

The Small Business Deduction: What It Means for Your Tax Bill

The small business deduction (SBD) is the reason a small corporation pays roughly 11% instead of roughly 26%. It cuts the federal rate on your first $500,000 of active business income from 15% to 9%, and every province layers its own lower rate on top.

To use it, your corporation generally needs to be a CCPC earning active business income. A few things can shrink or remove the benefit:

• Associated corporations share one $500,000 limit. If you or a related person control other corporations, you split it between them.
• Passive income above $50,000 starts reducing the limit. Large interest, rent, or investment income inside the corporation can eat into your SBD.
• Income above the limit gets taxed at the general rate. The extra isn’t lost, it just costs more.

Here’s what the gap looks like in real money. On $100,000 of income in Ontario, the small business rate costs about $11,200 and the general rate costs $26,500. That’s more than $15,000 a year in savings.

Example: Calculating Tax for a $100K Profit Business in Ontario

Say your Ontario CCPC has $100,000 of taxable active business income, and your tax year runs July 1, 2026 to June 30, 2027 (so the lower Ontario rate applies to the whole year).

Step	Calculation	Amount
Federal tax	$100,000 × 9%	$9,000
Ontario tax	$100,000 × 2.2%	$2,200
Total corporate tax		$11,200
Combined rate		11.2%
Left in the corporation	$100,000 − $11,200	$88,800

If your corporation has a calendar year-end instead (December 31, 2026), the Ontario piece blends the old and new rates. Ontario tax comes to about $2,700, total tax about $11,700, and the effective rate is roughly 11.7%.

Anyone searching for a corporate tax calculator Ontario will usually get a single flat number, so it’s worth checking whether the tool accounts for that July 2026 change.

Example: Calculating Tax for a $300K Profit Business in Alberta

Now an Alberta CCPC with $300,000 of taxable active business income. That’s under the $500,000 limit, so all of it gets the small business rate.

Step	Calculation	Amount
Federal tax	$300,000 × 9%	$27,000
Alberta tax	$300,000 × 2%	$6,000
Total corporate tax		$33,000
Combined rate		11%
Left in the corporation	$300,000 − $33,000	$267,000

What if profit jumps to $600,000? The first $500,000 stays at 11% ($55,000). The extra $100,000 gets taxed at the 23% general rate ($23,000). Total tax is $78,000, an effective rate of 13%.

Same logic applies in BC, just with different provincial numbers: 2% small business and 12% general.

Common Mistakes When Estimating Corporate Tax

Most estimate errors come from the same handful of slips.

1. Using accounting profit instead of taxable income. The two rarely match, and the gap can be large.
2. Using last year’s Ontario rate. Plenty of articles and calculators still show 12.2%. For tax years after July 1, 2026, the combined rate is 11.2%.
3. Forgetting associated corporations. Two companies under common control share one $500,000 limit, not two.
4. Ignoring passive income. Investment income above $50,000 can quietly reduce your small business limit.
5. Mixing up corporate tax and shareholder tax. The numbers above are tax inside the corporation. Paying yourself a salary or dividends triggers personal tax on top.
6. Missing payment dates. The balance is generally due two months after year-end (three months for many CCPCs), while the return itself is due six months after year-end. An online calculator is a great way to ballpark your bill, but it can’t see your associated corporations, passive income, or credits. For the real number, you need the full return.

Need help filing? Our corporate tax service handles this for you.

FAQ

Key Takeaways

• Corporate tax in Canada is federal plus provincial, calculated separately and added together.
• Qualifying CCPCs pay 9% federal on the first $500,000 of active business income, and 15% above that.
• Combined small business rates for 2026: Ontario 11.2% (from July 1), Alberta 11%, BC 11%.
• Start from taxable income, not accounting profit, and watch for associated corporations and passive income.
• A calculator is for estimates only. Your filed return decides the real bill.