Sole Proprietorship vs Corporation in Canada: The Comparison That Decides It

The question is almost always asked as “which one pays less tax”, and that is the wrong question. Canada’s tax system is built so that income earned through a corporation and paid out to you attracts roughly the same total tax as income you earned personally. On money you take out and spend, the difference is small.

The difference is on money you do not take out. That single mechanic, deferral, decides most cases. Everything else on the list matters, but it matters second.

Deferral is the actual mechanism

A sole proprietor is taxed personally on 100% of business profit, at personal marginal rates, whether the money stays in the business bank account or not. There is no such thing as leaving profit in a sole proprietorship. The CRA does not recognise a separation between you and it.

A corporation is a separate taxpayer. Active business income up to the business limit is taxed at the small business rate, which is far below the top personal rate. Personal tax only arrives when you pay yourself. If you earn $250,000 and live on $110,000, the corporation holds the remainder having paid only corporate tax on it, and that capital compounds on a larger base.

If you earn $95,000 and spend $95,000, that advantage is worth nothing to you. Incorporating costs money and produces no deferral, because there is nothing to defer.

So the first question is not about tax at all. It is: how much of your profit do you actually need to live on?

Side by side

Two rows deserve more than a cell.

Losses in the early years

This is the most under-weighted item in the comparison, and it points the opposite way to most advice.

A sole proprietorship loss reduces your other income in the same year. If you left a salaried job in June and lost $30,000 building the business by December, that loss lands against six months of T4 income and generates a refund now.

A corporation’s loss does nothing for you personally. It becomes a non-capital loss inside the corporation, waiting for the corporation to make money. If the corporation takes three years to turn a profit, the value of that deduction has been sitting idle for three years.

Which is why “incorporate on day one” is frequently wrong for a business that will lose money before it makes money, and frequently right for a consultant who is profitable in month one.

The exemption on sale

If you ever sell the business, the structure you chose years earlier decides whether the lifetime capital gains exemption is available. The exemption, currently $1.25 million on qualified small business corporation shares, applies to a sale of shares. A sole proprietor sells assets and goodwill, and no exemption applies to that.

The qualification tests are not satisfied on the day you decide to sell. They look back, including a 24-month holding period and asset composition tests. A business incorporated three months before a sale generally does not qualify. The tests, and the purification work that has to happen before the clock starts, are covered in lifetime capital gains exemption planning.

The gain itself is taxed at the one-half inclusion rate. The proposed increase to two-thirds was cancelled in March 2025, so any modelling built on the two-thirds figure is out of date and overstates the tax on a sale.

What limited liability really covers

Incorporation genuinely separates the corporation’s debts from your personal assets, and for a business with inventory, premises, employees or physical risk that is a substantial protection.

It is oversold for a solo service business, because three large holes remain.

Personal guarantees. Any lender or landlord dealing with a new corporation with no assets will ask you to guarantee the obligation personally. Once you sign, the corporate veil is irrelevant to that debt.

Your own negligence. A corporation does not shield you from liability for work you personally performed badly. Professional indemnity insurance does that job, and a regulated profession has its own structure rules in any case, set out in professional corporations in Ontario.

Director liability to the CRA. Directors are personally liable for unremitted payroll source deductions and unremitted GST/HST. This is the exposure that surprises owners most, and it is explained in directors’ liability.

The decision

Do you need essentially all of the profit to live on?
├─ YES ──> SOLE PROPRIETORSHIP for now. There is no
│          deferral to capture, and the corporate
│          overhead is a real cost.
└─ NO (you can leave meaningful profit behind)
   │
   Is the business currently losing money?
   ├─ YES ──> STAY UNINCORPORATED until profitable, so
   │          the losses land on your personal return.
   └─ NO
      │
      Do you serve essentially ONE client, doing work
      an employee would do?
      ├─ YES ──> STOP. Read the personal services
      │          business rules first. Incorporating
      │          could make your position worse.
      └─ NO
         │
         Might you sell the business one day, or do you
         face real liability or want to income split?
         ├─ YES ──> INCORPORATE, and do it early enough
         │          that the LCGE tests can be met.
         └─ NO ───> Incorporate when retained profit
                    is large enough that the deferral
                    exceeds the annual compliance cost.

The one that ruins the analysis

If your corporation earns its income from essentially one client, doing work that looks like employment, the personal services business rules may apply. A PSB is denied the small business deduction, taxed at a punitive rate, and denied most deductions other than salary paid to the incorporated employee. Everything above collapses.

This is not a rare edge case. It is the single most common way an incorporated contractor in Ottawa ends up worse off than they were as a sole proprietor. Establish the answer before you incorporate, not after a CRA review.

The costs and the constraints

Passive income grinds the small business rate. Once the corporation is holding retained earnings, the investment income they generate reduces the business limit. The grind begins at $50,000 of adjusted aggregate investment income across the associated group and eliminates the business limit entirely at $150,000. Check the current thresholds and the business limit itself on the CRA page before modelling. More detail in the passive income grind.

CPP works differently. A sole proprietor pays both the employee and employer halves of CPP on business income, calculated on Schedule 8 and deducted in part at line 22200. An incorporated owner pays CPP only on salary, which is a genuine saving and also a genuine reduction in future benefits and RRSP room. See self-employed CPP contributions.

Deadlines get tighter, not looser. A sole proprietor files by 15 June but must pay by 30 April. A corporation files six months after year end but must pay the balance two months after year end, or three months for a CCPC claiming the small business deduction and meeting the conditions on the CRA’s balance-due day page. Corporate instalments start once tax payable is above the threshold.

What does not change. The GST/HST small supplier threshold applies the same way to both. So do the record retention rules, the audit exposure and the quality of bookkeeping you need. Incorporation is not a substitute for records.

Switching later

Moving an existing sole proprietorship into a corporation is a disposition of assets at fair market value unless you elect otherwise. The election, a section 85 rollover, transfers assets at an agreed amount and defers the gain. It is routine work, it is not free, and it has to be filed on time.

The practical implication is that starting unincorporated does not close the door. You can run as a sole proprietor while the business finds its footing and incorporate once the profit is real, and that sequence is usually cheaper than incorporating early and carrying the compliance cost through the loss years. The provincial and structural mechanics of doing it are in when to incorporate in Ontario.

What to do

Take last year’s actual net profit and subtract what you genuinely needed to live on. If that number is small, the answer is almost certainly to stay as you are for another year. If it is substantial and recurring, run the incorporation numbers properly, and settle the personal services business question first.

If you are close to the line, or you are being told to incorporate by someone who has not asked what you take out of the business, a second opinion is worth having before the fees are spent.