Keep your Canadian investment cost history together, understand how purchases and adjustments change ACB, and review gains when you sell. Start with a free account for an ongoing saved ledger.
Try the free one-security ACB calculator
T5008 difference explained: Broker used account-local ACB. myCostBase used pooled ACB across WS + QT accounts, adjusted for ROC.
Adjusted cost base (ACB) is your investment’s cost for tax purposes, including purchase commissions and subsequent adjustments. myCostBase keeps that history in one ledger across taxable brokerage accounts, so you can review the ACB used when you sell and the resulting capital gain or loss. Read what adjusted cost base means for the full definition, or the ACB calculation example for two purchases and a partial sale.
A broker figure can be a useful cross-check, but one institution may not have outside holdings, complete transfer history, or every adjustment needed for your tax calculation. myCostBase gives you one place to reconcile those records.
Box 20 reports cost or book value. CRA says it may or may not reflect ACB, so compare it with your records and the adjustments applicable to the disposition.
myCostBase: Compares your ledger ACB with T5008 figures by security, highlights the difference, and exports a reviewable disposition summary.
Hold the same ETF at Questrade and Wealthsimple? Canadian tax law requires one pooled ACB across both. Neither broker can calculate that for you. See supported brokers for the full list.
myCostBase: Pools identical-property holdings across every taxable account for the same taxpayer — automatically, following documented CRA identical-property rules.
Positive T3 Box 42 amounts generally reduce ACB. If those adjustments are missed, a later capital gain can be understated or a capital loss overstated.
myCostBase: Records ROC adjustments, DRIP reinvestments, and reinvested gains as dated ledger events so the year-end calculation remains reviewable.
Convert foreign-currency purchases and dispositions separately, retain the rate source and date, and apply the selected method consistently.
myCostBase: Fetches Bank of Canada daily rates per transaction, shows the rate source inline, and supports documented overrides that stay in the audit trail.
Add accounts
Assign each account to its taxpayer and identify taxable and excluded accounts.
Import or enter history
Preview supported CSV files or enter transactions manually, then resolve missing history.
Reconcile and export
Review the ledger against your source documents and use the reports included in your plan.
Every security has a running ledger showing share count, total ACB, and ACB per share after each event. When a number moves, the explanation sits next to the row that caused it — so you can defend the calculation, not just report the result.
Keep your calculations in a saved account as your holdings change. Create your free account to start with manual entry or your first 100 CSV transactions. Full ledger details and exports depend on your plan.
If you maintain an adjusted cost base spreadsheet, myCostBase gives you a structured running ledger for ongoing records. Keep one transaction history when the same security is held across multiple taxable brokerage accounts, with ETF adjustments, transfers, and foreign-currency transactions recorded alongside the changes to your ACB.
Date, brokerage account, quantity, commission, currency, and the source row that produced it.
Shares and ACB before and after, realized gain or loss, and the specific rule applied to reach the number.
Manual adjustments, Bank of Canada FX overrides, and warnings stay attached to the ledger for later accountant review.
myCostBase is built for non-registered taxable accounts where ACB tracking actually gets complicated: the same ETF at two brokerages, USD positions that need daily FX conversion, ETF distributions that change your cost base annually, and transfers that carry original cost forward across institutions.
Explore all features →myCostBase follows the rules Canadian tax law actually requires — not a simplified approximation of them.
ACB pooling, return-of-capital adjustments, and USD FX conversion are applied according to the rules CRA actually uses — not the account-local book value method brokers default to. The methodology is documented and inspectable, so you can verify what the system is doing, not just trust the output.
Documented methodology, not a proprietary black box
Capital gains summaries, disposition detail, and ACB audit trails are formatted for the moment your accountant asks for backup. The ledger produces well-documented capital gains figures for filing software like TurboTax or UFile — so nothing needs to be reconstructed under deadline when T5008 season arrives.
Export-ready before tax season, not after it
myCostBase is a ledger, not a filing tool. It produces the correct ACB and capital gains summary your accountant needs — and exports the detail required by software like TurboTax or UFile.
Export-ready for filing season
Add accounts from any Canadian brokerage. Import CSV trade history, enter transactions manually, or mix both. Your data is not tied to a single institution's export format or book value assumptions.
Any brokerage, any account structure
Practical guides on adjusted cost base, T5008 reconciliation, and Canadian tax calculations for investors in taxable accounts.
Adjusted Cost Base
Document a spin-off cost allocation using issuer tax materials, Canadian rules, and manual ledger adjustments without inventing acquisition cost.
Canadian Tax Basics
Understand gains and denied losses when contributing shares in kind to a TFSA or RRSP, with examples and records to check before transferring.
Canadian Tax Basics
Establish the cost of inherited shares using estate records, date-of-death values, and rollover details before adding them to your taxable ledger.
How the application calculates ACB, what you can do for free, and how to keep your history reviewable.
Free plan includes unlimited manual entry.