What is adjusted cost base in real estate?

Understanding your property's Adjusted Cost Base is crucial before selling any investment property or non-exempt principal residence in Calgary. A higher ACB means a smaller taxable capital gain — and that difference can be worth tens of thousands of dollars.

ACB at a glance

When you sell a property, the capital gain is: Sale proceeds − ACB − Selling costs. The ACB starts at what you paid for the property (including legal fees, home inspection, and any other acquisition costs). It then increases with each qualifying capital improvement made during your ownership.

What increases ACB

Capital improvements that extend the useful life of the property or add a new asset increase ACB. Examples for Calgary real estate: building an addition, finishing a basement, installing a new roof, replacing a furnace or hot water tank with a higher-capacity unit, adding a garage, building a deck, replacing all windows. The key test: does this create something new or extend the life of something significantly? Or is it just maintenance?

What does not increase ACB

Routine maintenance and repairs do not increase ACB, even if they cost significant money: repainting, replacing a broken furnace with an equivalent unit, fixing a leaking roof (vs replacing it), patching drywall, replacing carpet with equivalent carpet. These are considered costs of maintaining the property's value, not adding to it.

Why documentation matters

CRA requires you to substantiate your ACB with documentation — receipts, contracts, and invoices for each capital improvement. Without documentation, CRA can challenge the ACB and assess the capital gain based on the original purchase price only. Keep every renovation receipt for as long as you own the property and for six years after the year you sell.

ACB for inherited or gifted property

When you inherit a property (through an estate), your ACB is the property's FMV at the date of the deceased's death — the same amount that triggered the deemed disposition. When you receive a property as a gift (from a living person), the ACB depends on whether the transfer was at arm's length and whether the gifting person elected to transfer at FMV or their own ACB.

Frequently asked questions

Do legal fees on purchase increase my ACB?

Yes. Legal fees paid to acquire the property — including your real estate lawyer's fees on purchase — are added to your ACB. So are land transfer taxes (not applicable in Alberta) and any other costs directly associated with acquiring the property. Keep all closing documents from your original purchase.

Does a finished basement increase ACB?

Yes, if the finishing added significant value and was not previously finished. A basement developed from unfinished to a liveable space (drywall, flooring, electrical, plumbing for a bathroom) is a capital improvement that increases ACB. Keep all contractor invoices, permit records, and material receipts.

Does the Principal Residence Exemption eliminate the need to track ACB?

If the PRE fully shelters the gain, there is no tax regardless of ACB — but you still need to report the disposition on your T1 return. If the PRE only partially applies (e.g., you used the property as a rental for some years), accurate ACB documentation becomes critical to calculating the correct taxable gain.

Talk to Ryan Van Spengen

Calgary REALTOR® specialising in divorce, estate, and upsizing transactions. Free consultation — no obligation.

Book a free call

This page is for general information only and does not constitute legal or tax advice. Consult a qualified Alberta lawyer or accountant for advice specific to your situation.