Adjusted Cost Base Calculator
Track the average cost of a stock, ETF or fund, the gain or loss on each sale, return of capital and the superficial loss rule. Free and private.
The short version
- Enter every buy, sell and distribution for one stock, ETF or fund, in any order. You get the average cost per share, the gain or loss on each sale, and the totals by year.
- It applies the superficial loss rule automatically: a loss is denied in proportion when you buy back within 30 days and still hold the shares 30 days after the sale.
- Handles reinvested distributions, return of capital (with the negative-ACB rule) and notional distributions from your T3.
- Amounts in Canadian dollars. For U.S. stocks, convert each trade at that day's Bank of Canada rate first.
- Nothing you enter leaves your browser; your list is kept on this device only.
Adjusted Cost Base Calculator
Every investor eventually discovers that their broker's idea of their cost and CRA's idea of their cost are different numbers. CRA's is the one that counts. This calculator keeps the running average the way CRA wants it: every purchase averaged in, every sale taking out the average, distributions and losses adjusted the way the rules say. Enter the trades once, keep them here, add new ones as you go.
How to Enter Each Transaction
| Type | Shares | Amount | Fees |
|---|---|---|---|
| Buy | Units bought | Price times units, before commission | Commission |
| Sell | Units sold | Price times units, before commission | Commission |
| Reinvested distribution | Units received | Amount reinvested | Leave blank |
| Return of capital | Leave blank | T3 box 42 | Leave blank |
| Notional distribution | Leave blank | Capital gain distributed but not paid in cash | Leave blank |
The rules behind it are on adjusted cost base explained, and the slips on the T3.
Got a broker statement instead of a list?
Paste or describe the trades. The assistant turns them into the transaction list for this calculator and explains anything unusual, like a spin-off or a merger.
Reading the Result
- Cost per share now is what you'd use for the next sale.
- Gain or loss by year goes on Schedule 3; half is taxable. The tax at your income is in the capital gains calculator.
- Loss denied (superficial) isn't gone; it's in the cost of the shares you still hold. Details on capital losses and the superficial loss rule.
- Several stocks? Run each one separately. Each security has its own pool.
More for investors: stock investment taxes, foreign tax credit and investment taxes.
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ACB Calculator Questions
How do I calculate adjusted cost base for multiple purchases?
Keep a running total: add the cost and commission of each purchase, and divide by the units held. When you sell, remove the units at the current average cost. The calculator does this for every transaction you enter.
Does the ACB calculator handle the superficial loss rule?
Yes, for the transactions you enter. It cannot see purchases by your spouse, your corporation or in your registered accounts, which also count.
How do I enter return of capital?
Choose Return of capital and enter the amount from box 42 of your T3 slip. It reduces your ACB; if the ACB would go below zero, the excess is shown as a capital gain.
Can I use this for U.S. stocks?
Yes, after converting each trade to Canadian dollars at the Bank of Canada exchange rate for that day.
Is my data saved?
Only in your browser on this device, so you can come back and add trades. Nothing is sent to our server.
Can I use the ACB calculator for crypto?
Yes. Enter each coin separately in Canadian dollars. A trade of one crypto for another is a sale of the first and a purchase of the second, at fair market value.
Sources: CRA, Guide T4037, Capital Gains. Checked October 2026. Corporate actions such as spin-offs, mergers and stock options are not handled automatically; enter them as advised by the issuer. The superficial loss calculation follows the proportional formula CRA describes for partial repurchases.
Last reviewed October 5, 2026 against CRA and Government of Canada sources. How we check our facts.