Incorporated professionals get told incorporation saves tax. It is more accurate to say incorporation defers tax, and that the deferral is only worth something if you have a plan for what the money does while it sits there and how it comes out later.
This guide covers the decisions that actually recur: whether to incorporate, how to pay yourself, what to do with retained earnings, and what the whole structure means when you stop practising. It is written for physicians, but applies equally to dentists, lawyers, accountants, engineers and consultants operating through a corporation.
What incorporation actually does
A professional corporation earning active business income in Canada is generally eligible for the small business deduction, which taxes that income at a substantially lower rate than personal rates, up to a business limit, currently $500,000 of active income federally, shared among associated corporations.1 Provincial rates and limits vary.
The key point is what happens next. That low rate applies only while the money stays in the corporation. When you pay it to yourself as a dividend, personal tax applies. The system is designed so that earning through a corporation and paying it all out leaves you in roughly the same place as earning it personally, a principle called integration.
So incorporation is not a discount. It is a deferral, and the deferral is valuable in proportion to how long the money stays invested inside the corporation and how much lower your tax rate is when it eventually comes out.
The most common expensive mistake we see is incorporating too early.
If you are spending essentially everything you earn, as many people do in the first years after residency with student debt, a mortgage and a young family, there are no retained earnings to defer tax on. What you get instead is accounting fees, a corporate return, payroll obligations and administration, in exchange for a benefit you are not in a position to use.
Incorporation starts to pay when there is money you genuinely do not need to spend this year. Until then, the question is not "should I incorporate" but "when will I be able to leave money in".
Salary or dividends
Once incorporated, you choose how to extract money. The two routes are not equivalent, and the difference is structural rather than a matter of rates.
Salary is deductible to the corporation. Paying it reduces corporate income, so it is never taxed corporately, only personally. It also creates RRSP contribution room, at 18% of earned income up to an annual dollar maximum,23 and it requires CPP contributions from both you and the corporation.4
Dividends are paid from income the corporation has already been taxed on, and are not deductible. They create no RRSP room and no CPP contributions, and therefore no CPP entitlement, but they avoid payroll administration.
| Salary | Dividends | |
|---|---|---|
| Deductible to the corporation | Yes | No |
| Creates RRSP room | Yes, 18% of earned income, to an annual maximum | No |
| CPP contributions | Required, both employee and employer share | None, and no CPP entitlement built |
| Payroll administration | Source deductions, T4s, remittances | T5 slips only |
| Counts as income for mortgage qualification | Usually straightforward | Often needs two years of history |
Try it with your own numbers
This compares what you keep under different splits. Set the rates for your province and income level, that is why they are inputs rather than assumptions baked into the tool.
Rates are yours to set because they depend on your province and income level. The corporate rate is the small-business rate on active income; the dividend rate is your effective rate after the dividend tax credit. Salary is treated as deductible to the corporation, so only the remainder is taxed corporately and then paid out as a dividend.
How to read it. The net cash figures for all-salary and all-dividends are usually close together, which is integration working roughly as intended. The decision is therefore rarely won on the net cash line. It is won on the things the calculator shows alongside it: the RRSP room salary creates, the CPP entitlement it builds, and the corporate tax that retained income attracts.
Two caveats about the RRSP figure. It shows the room the salary generates at 18%, without applying the annual dollar maximum, because the point is to show the tradeoff rather than the filing result, check the current year's cap before acting.3 And it ignores any pension adjustment, which matters if you have an individual pension plan.
What to do with retained earnings
Money left in the corporation has to go somewhere, and an investment account inside a corporation does not behave like an RRSP.
Investment income earned inside a corporation is taxed at high rates, and passive investment income above a threshold grinds down the small business deduction available on active income, eliminating it entirely at a higher threshold.1 A corporation that accumulates a large passive portfolio can therefore lose access to the low rate on the practice income that generated it.
That does not make corporate investing wrong. It makes it something that needs an actual investment policy: what is held inside the corporation versus personally, how income is generated, and in what order accounts are drawn down later.
The ordering question is usually the more valuable one. Before retaining earnings, most incorporated professionals should have considered:
- TFSA room, which produces tax-free growth and tax-free withdrawals
- RRSP room, if salary has created it
- Non-deductible debt, particularly a mortgage
- Whether an individual pension plan fits, which can allow larger deductible contributions than an RRSP at older ages
Planning for leaving practice
The corporation does not stop mattering when you stop working. That is when the accumulated decisions come due.
- Withdrawal sequencing. Corporate dividends, RRSP and RRIF withdrawals, TFSA and non-registered accounts each have different tax treatment, and the order changes lifetime tax materially.
- OAS clawback. Corporate dividends count toward the income that triggers OAS recovery. A corporation drawn down carelessly can cost OAS that better sequencing would have preserved.
- Winding up. Extracting a large corporate balance over a short period stacks it into high tax brackets. Drawing it down over more years, often starting before you fully retire, usually costs less.
- Estate. Shares of a professional corporation held at death raise both liquidity and double-taxation issues that need planning well in advance.
Retirement planning for an incorporated professional is mostly a sequencing problem, not an investment problem.
Two doctors with identical corporations, identical portfolios and identical spending can end up with materially different lifetime tax and different amounts left to their families, purely from the order in which accounts were drawn and when CPP and OAS were started. That difference is decided in the decade before and the decade after leaving practice, and it is largely irreversible once the withdrawals have happened.
Questions worth asking your own advisors
- Given what I actually spend, how much will realistically stay in the corporation each year?
- What salary do I need to create the RRSP room I want, and do I want it?
- How close is my passive income to the threshold that reduces the small business deduction?
- What order will accounts be drawn in, and what does that do to OAS?
- If I stopped practising in five years, how long would drawing the corporation down take?
Sources
- Canada Revenue Agency, T2 Corporation Income Tax Guide, Chapter 4 - small business deduction and the business limit (accessed 2026-07-28)
- Canada Revenue Agency, How contributions affect your RRSP deduction limit (accessed 2026-07-28)
- Canada Revenue Agency, MP, DB, RRSP, DPSP, ALDA, TFSA limits, YMPE and YAMPE - current year dollar limits (accessed 2026-07-28)
- Government of Canada, Canada Pension Plan contributions (accessed 2026-07-28)
About the author
Calgary-based Certified Financial Planner, holding the CFP designation since 2002. He acts as an expert witness and litigation analyst for the legal community, and has served on the boards of the Alberta Insurance Council and the Estate Planning Council of Canada.
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