Disclaimer This is a simplified ESTIMATE ONLY. It ignores tax brackets, credits, dividends vs salary optimization, provincial variations, the $500,000 small business limit phase-outs, and integration on later withdrawal — the deferral is not a permanent saving. Incorporation decisions require a CPA or tax lawyer.
Deciding whether to incorporate is the single most common tax-structure question Canadian business owners bring to their accountant, and the honest answer is always numeric: how much income will actually stay in the company, and what does that deferral earn against the cost of maintaining a corporation? This calculator puts a first number on it in about thirty seconds, using the same sole-proprietor-versus-CCPC comparison a professional would sketch in a first meeting — so you arrive at that meeting knowing whether the conversation is worth having.
Incorporating saves tax in Canada primarily through deferral. A Canadian-controlled private corporation (CCPC) pays the combined federal-provincial small business rate — roughly 9% federal plus 2–3.2% provincial, or about 11–12.2% total — on the first $500,000 of active business income. A sole proprietor pays personal rates on every dollar the year it is earned, up to 53.5% at the top Ontario bracket. The gap between those rates, applied to income you can afford to leave in the corporation, is the deferral this calculator estimates.
The critical nuance is integration: when you eventually pull retained earnings out as dividends, personal tax applies and the total burden roughly catches up to what a sole proprietor paid. The advantage is timing — money compounds inside the corporation at 88–89 cents on the dollar instead of 47–57 cents, and you control which year (and at which bracket) you take it out.
A consultant earns CA$150,000 of net business income in Ontario and needs CA$80,000 of salary to live. As a sole proprietor at a 43% marginal rate the estimated tax is CA$64,500. Incorporated, the CA$80,000 salary is taxed personally (CA$34,400 at the same marginal assumption) and the CA$70,000 retained is taxed at Ontario's 12.2% small business rate (CA$8,540) — total CA$42,940, an annual deferral of roughly CA$21,560 that keeps working inside the company.
Incorporation is not free money. Budget CA$1,000–CA$2,000 to incorporate (federal or provincial), CA$1,500–CA$4,000 a year for corporate tax returns (T2) and bookkeeping, plus annual registry filings. You take on payroll remittance obligations the moment you pay yourself a salary, and directors are personally liable for unremitted source deductions and GST/HST. The corporation also files its own return even in a loss year. A useful rule: if the modelled annual deferral is less than about three times the annual compliance cost, the paperwork usually isn't worth it yet — revisit the numbers as income grows, since the deferral scales with retained earnings while compliance costs stay roughly flat. Many owners find the crossover arrives somewhere between CA$100,000 and CA$130,000 of net income, though liability protection or an anticipated business sale can justify incorporating earlier.
Treat every figure here as a planning estimate. Real outcomes depend on your province, salary-versus-dividend mix, passive investment income (which can grind the small business limit above $50,000 of passive income), and payroll obligations once you pay yourself a salary — model those with our true cost of an employee calculator. Speak with a CPA before incorporating; if you're a law firm advising incorporations, LexScale.ai builds client-facing tools like this one to capture that demand.
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