Lifetime Capital Gains Exemption Calculator for a Share Sale
Selling the shares of your corporation can be largely tax free, but only up to a limit and only after several things reduce it. Work out what exemption is actually available, the tax on what is left, and what spreading the sale across family members is worth.
net after tax
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The Gain and the Exemption
| Item | Basis | Amount |
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Tax on What Is Left
| Item | Basis | Amount |
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Spreading the Sale Across a Family
| Claimants | Exemption Used | Taxable Gain | Tax |
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Points That Decide This
What to Do Next
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Disclaimer: The lifetime capital gains exemption is provided by section 110.6 of the Income Tax Act in respect of capital gains realised on the disposition of qualified small business corporation shares and certain farm and fishing property. Whether shares are qualified small business corporation shares depends on tests that include the proportion of the corporation’s assets used principally in an active business carried on primarily in Canada, measured both at the time of disposition and throughout the twenty-four months preceding it, and on a holding period requirement; those tests are not applied by this page. The exemption is a lifetime limit that is reduced by amounts claimed in prior years, and the amount deductible in a year is further restricted by the taxpayer’s cumulative net investment loss balance and by allowable business investment losses, each of which operates under its own rules. The capital gains inclusion rate has been the subject of proposed legislative changes and subsequent reversals in recent years, so the rate applicable to a particular disposition must be confirmed for the year in question rather than assumed. Claiming the exemption commonly gives rise to exposure under the alternative minimum tax, the computation of which involves an adjusted taxable income base, a basic exemption, a separate rate and the inclusion of a portion of otherwise exempt capital gains, together with restrictions on credits and deductions; the figure shown on this page is a simplified indication produced from editable inputs and is not a computation of minimum tax, which should be prepared properly before any sale is completed. Minimum tax paid may generally be carried forward and recovered against regular tax in later years, subject to conditions. Arrangements under which family members hold shares so that more than one exemption may be claimed raise questions under the attribution rules, the tax on split income, section 84.1 and the general anti-avoidance rule, and a structure put in place shortly before a sale is unlikely to achieve the intended result. This page is general information, not tax advice, and no transaction should proceed on the strength of it.
The Exemption Is Not the Headline Number
People hear a figure over a million dollars and assume that is what they will get. The lifetime limit is the starting point, and three separate things can reduce what is actually deductible in the year of sale.
Prior claims come off it, because the limit is lifetime rather than per sale. A cumulative net investment loss balance restricts it. And allowable business investment losses claimed in earlier years reduce it as well.
The CNIL balance is the one nobody expects. It builds up when investment expenses exceed investment income over the years, which happens quietly to anyone who has carried interest on an investment loan. It sits in the background for decades and then appears at the worst possible moment, reducing the exemption on the sale of a lifetime.
Qualifying Is a Separate Question, and It Is Not Automatic
The exemption applies to qualified small business corporation shares. That means asset tests measured both at the moment of sale and across the two years before it, plus a holding period.
A profitable company that has accumulated cash, investments or a surplus building can fail those tests without anyone noticing, because the assets that make it comfortable are the assets that make it non-qualifying. Fixing that is called purification and it takes time, which is precisely what a letter of intent does not leave you.
Check eligibility before negotiating, not after. The asset tests look back twenty-four months, so a company that fails today cannot be made to qualify by next month. Our QSBC eligibility and purification checker works through those tests.
Minimum Tax Is the Surprise in the Year of Sale
Claiming a large exemption often triggers alternative minimum tax. A portion of the gain that the exemption makes tax free is nevertheless brought into the minimum tax base, and the result can be a substantial cheque in a year the seller expected to pay nothing.
It is usually recoverable against regular tax in later years, subject to conditions, so it is often a timing cost rather than a permanent one. But it is real cash in the year of the sale, and a seller who has committed the proceeds elsewhere can be caught badly.
The minimum tax figure on this page is an indication, not a computation. Minimum tax has its own base, its own exemption and its own treatment of credits and deductions, and it interacts with everything else on your return. It needs calculating properly before a sale closes rather than estimating.
Multiplying Across a Family Works, If It Was Done Early
Each individual has their own lifetime exemption. Where a spouse and adult children genuinely hold shares, each can potentially claim against their own gain, and on a large sale that multiplies the tax-free amount considerably.
The difficulty is that this only works if the structure was in place well before the sale and the shares were genuinely acquired. A reorganisation carried out once a buyer is at the table attracts attention from several directions at once.
| Arrangement | How It Tends to Be Viewed |
|---|---|
| Family trust set up years before any sale | Ordinary planning |
| Shares issued to family in the normal course | Ordinary planning |
| Reorganisation after a letter of intent | Scrutinised closely |
| Shares to family members with no involvement or funds | Attribution and split income rules |
The Inclusion Rate Has Moved Recently
The proportion of a capital gain brought into income has been the subject of proposed changes and reversals in the last few years. That makes it one of the few inputs on a page like this that genuinely has to be confirmed for the year of the disposition rather than assumed.
It is an editable field here for that reason. Changing it changes every figure below, and getting it wrong changes the answer substantially on a sale of this size.
What This Calculator Does Not Cover
- Whether the shares qualify, which is the first question and a separate one
- The proper minimum tax computation, which needs your whole return
- Section 84.1, where the buyer is a family member or a corporation they control
- Earnouts and deferred proceeds, and the reserve rules that apply to them
- An asset sale, which is taxed entirely differently and often preferred by buyers
- Attribution and split income rules where family members hold shares
The planning has to happen before the buyer arrives. Our capital gains tax planning service covers eligibility, purification, the CNIL position, minimum tax modelling and whether the family structure will stand up, all of which are considerably easier to deal with before a sale process starts.
Frequently Asked Questions
Common questions on selling shares and the exemption.
Related Calculators and Guides
More on selling a business.
Check the Position Before You Sign Anything
Send us the structure, the proposed terms and your prior exemption and CNIL position. We will confirm whether the shares qualify, what exemption is genuinely available, what minimum tax falls due in the year of sale, and whether the family arrangement will hold up.