Answers · Incorporation and Not-for-Profits
Sole proprietorship or corporation: how do the taxes compare?
As a sole proprietor, every dollar of profit is taxed on your personal return in the year you earn it, at your marginal rate, which in Ontario can reach roughly 53.53% at the top bracket, and you pay both the employer and employee halves of CPP on your net business income. A corporation pays tax on active business income at a much lower rate first, often around 12.2% combined federal and Ontario under the small business deduction, and you only pay personal tax on the salary or dividends you actually take out. When you withdraw everything the corporation earns each year, the two systems land close to the same total tax through a mechanism called integration; the corporation’s real advantage shows up when you leave profit inside it to reinvest, deferring the personal-level tax until later.
By the AnalytIQ Accounting team · Last reviewed: September 6, 2026
How a sole proprietorship is taxed
A sole proprietor reports business income and expenses on form T2125, attached to their personal T1 return, and the net profit is simply added to whatever else they earned that year, taxed at their personal marginal rate. There is no separate corporate rate to access; the first dollar of profit and the last dollar are both taxed on the same personal scale, which in Ontario climbs to roughly 53.53% combined federal and provincial tax at the top bracket. A sole proprietor also pays both the employee and employer portions of CPP on their net self-employment income, since there is no employer to split the contribution with, which is a cost incorporated owners paying themselves dividends do not have on that portion of their income.
How a corporation is taxed instead
A corporation files its own T2 return and pays tax on its active business income directly, generally at a combined rate around 12.2% in Ontario on the first $500,000 through the small business deduction, well below most owners' personal marginal rate. That low rate only applies inside the corporation; when money moves out to you personally, as salary or as a dividend, it is taxed again on your personal return. Salary is deductible to the corporation and taxed to you as employment income, while dividends are not deductible to the corporation but come with a personal dividend tax credit that accounts for the corporate tax already paid, a system covered in more detail in T4 or T5 as an owner-manager.
Why the two systems land close together if you take everything out
Canada's tax system is built around integration: the idea that whether income is earned personally or through a corporation and paid out as a dividend, the combined corporate and personal tax should come out close to the same total. In practice it is not perfectly neutral, sometimes slightly favouring one route depending on the income level and dividend type, but it is close enough that incorporating purely to reduce tax on money you plan to spend every year rarely delivers the dramatic savings owners sometimes expect. The real tax advantage of a corporation is not the rate on money you withdraw; it is the rate on money you leave behind.
Where the corporation actually wins: reinvested profit
If a business generates more profit than the owner needs to live on, a corporation lets that surplus sit inside the company taxed at roughly 12.2% instead of being pulled out and taxed immediately at a personal marginal rate that could be more than four times higher. That gap is a genuine deferral, not a permanent saving, since personal tax eventually applies when the money is withdrawn, but deferring it means more after-tax dollars are available to reinvest in inventory, equipment, or hiring in the meantime. A sole proprietor has no equivalent option; profit is taxed in full the year it is earned whether it is spent, saved, or reinvested.
What incorporating does not change
GST/HST registration rules are identical either way: both a sole proprietor and a corporation register once revenue crosses, or is expected to cross, the $30,000 small supplier threshold, and both charge and remit HST the same way after that. Incorporating also does not exempt you from paying yourself something reasonable to live on; whatever a corporation pays out as salary or dividends is still taxed personally, just at a different rate and on a different timeline than a sole proprietor's profit. The tax comparison is really about the rate and timing on income, not about which structure lets you avoid tax on money you actually need to spend.
Liability is a separate consideration from tax entirely, and it is worth not letting the tax comparison crowd it out. A sole proprietor is personally on the hook for the business's debts and legal claims without limit, while a corporation generally separates the business's liabilities from the owner's personal assets, subject to the usual exceptions for personal guarantees and unpaid source deductions. For some owners, this protection matters more than the tax difference either way.
| Sole proprietorship | Corporation |
|---|---|
| All profit taxed personally the year it is earned, at marginal rates | Active business income taxed inside the corporation first, around 12.2% up to $500,000 |
| Files T2125 with your personal T1; no separate corporate return | Files its own T2 return, plus a T1 for whatever you pay yourself |
| Pays both CPP halves on net self-employment income | CPP applies only to salary you choose to pay yourself, if any |
| Business losses can offset other personal income the same year | Losses stay inside the corporation, carried back or forward against its own income |
Why losses point some owners the other way
A sole proprietor's business losses flow directly onto the personal return and can offset employment income, investment income, or a spouse's income in the same year, which is genuinely useful for a business that is still losing money in its early years. A corporation's losses stay trapped inside the corporation, only usable against the corporation's own income in another year, which does the owner no immediate personal good. This is one of the clearer reasons a new business expecting a few years of losses sometimes starts as a sole proprietorship and incorporates once it turns profitable, a decision covered more fully in should I incorporate my small business in Ontario.
How we handle this
We run the actual numbers rather than a rule of thumb: your expected profit, how much you need to withdraw to live on, and whether losses in the early years are likely, before recommending either structure. This sits alongside our incorporation and compliance services for owners deciding whether the timing is right to move from a proprietorship to a corporation.
Related questions.
At what profit level does incorporating start to save tax?
It depends on how much you need to withdraw versus how much you plan to leave inside the business, so there is no single dollar figure that applies to every owner; it is worth modelling against your actual numbers rather than a generic rule of thumb.
Do I still need to file a personal return if I incorporate?
Yes. A corporation files its own T2, and you separately file a personal T1 reporting whatever salary or dividends you paid yourself out of the corporation that year.
Can I switch from a sole proprietorship to a corporation later without starting over?
Yes, most owners transfer an existing sole proprietorship into a new corporation using a section 85 rollover, which defers tax on the transfer rather than triggering it.
Related reading
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