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Your crypto adjusted cost base is what you paid in Canadian dollars plus the fees to buy. CRA guide T4037 averages the cost of identical properties, and many preparers apply that to units of one coin. A partial sale uses the average and leaves the rest unchanged.
What is the adjusted cost base of crypto?
The adjusted cost base, or ACB, is the amount you subtract from your proceeds to find a capital gain or loss. The CRA's capital gains guide T4037 describes it as usually the cost of a property plus the expenses to acquire it, such as commissions and legal fees. For crypto the CRA says a gain is the proceeds minus the ACB minus the outlays and expenses of selling.
The ACB belongs to each type of coin on its own. The CRA valuing page says each type of crypto-asset is valued as its own asset. You keep one running ACB for each coin, and it moves up when you buy more and down when you sell some.
The cost is in Canadian dollars. If you paid in another currency, the CRA says to convert at the rate in effect when you acquired the property. Our page on reporting crypto on your 2026 return shows where the result lands on Schedule 3.
Which transaction fees count toward the cost?
The cost is the price you paid plus the reasonable costs of buying. T4037 names commissions and legal fees as examples of expenses to acquire a property. In crypto that usually means the trading fee on the purchase. Selling fees are different. They are outlays and expenses of the sale, so they reduce your proceeds and do not change the ACB.
The CRA valuing page says that when you buy with another coin, the cost is the fair market value in Canadian dollars at the time of the purchase, found with a reasonable method that you use every year. Network fees paid in coin are not covered by a CRA crypto page we could read, so we do not state a rule for them. Keep the amount and date.
T4037 also says current repair and maintenance costs cannot be added to a cost base. That wording is about physical property, and it has little to do with coins. It is still a reminder that only costs of acquiring the property count.
How does averaging identical coins work?
T4037 has an identical properties rule. It says that when you own several identical properties, for example shares of the same class of a corporation or units of a mutual fund trust, you work out the average cost of each property in the group every time you buy more. That average is your ACB per unit. The same section says that selling some of them does not change the ACB of the ones you keep.
The calculation divides the total cost of everything you bought by the number of units you own. Here is an example with a made up coin, computed in a script.
| Lot | Units | Price paid | Fee | Cost |
|---|---|---|---|---|
| Purchase 1 | 0.5 coin | $20,000 | $50 | $20,050 |
| Purchase 2 | 0.5 coin | $30,000 | $50 | $30,050 |
| Total | 1 coin | $50,000 | $100 | $50,100 |
The total cost is $50,100 for 1 unit, so the ACB is $50,100 per unit. The order of the purchases does not matter once you average.
The unsettled point is whether the CRA treats units of one coin as identical properties. T4037 gives shares and fund units as the usual examples and does not mention crypto-assets, and the CRA crypto pages we read say nothing about averaging acquisition costs. Many preparers apply the rule to units of the same coin because they are interchangeable. We have not found a CRA page that says so, so confirm it with the CRA or a qualified professional before you rely on it.
What is left after a partial sale?
Say you sell 0.4 of the coin for $22,000 and pay a $100 fee. The ACB of the part you sold is 0.4 multiplied by $50,100, which is $20,040. The rest of the numbers follow.
| Step | Amount |
|---|---|
| Proceeds from selling 0.4 coin | $22,000 |
| Selling fee (an outlay) | -$100 |
| ACB of the 0.4 coin sold (0.4 x $50,100) | -$20,040 |
| Capital gain | $1,860 |
| Taxable capital gain (half) | $930 |
| Cost left on the 0.6 coin kept | $30,060 |
The CRA says half of the capital gain is taxable, so $1,860 gives $930. The 0.6 coin you still hold keeps the same ACB per unit, so its cost is $30,060. That is 0.6 times $50,100.
Now buy 0.4 more coin for $24,000 plus a $40 fee. The new total cost is $30,060 plus $24,040, or $54,100, for 1 unit. The ACB per unit resets to $54,100. Each new purchase starts a new average, and a sale uses whatever the average is on that day.
Do wallet transfers change the cost?
The CRA says transfers between wallets you own are not taxable dispositions. A transfer does not create a gain, and it does not reset your cost. The coin that arrives has the same ACB as the coin that left. Keep both wallet addresses in your records, because the CRA books and records page asks for them.
A transfer to someone else is different. A gift or a donation of crypto is a disposition under the CRA pages, so you work out a gain or loss on it. Paying for goods or services with coin is also a disposition, and the CRA treats it as barter. Our page on whether gifts are taxable covers the general gift rules.
What if the exchange report does not match your numbers?
Platform reports are a starting point. They may use a cost method different from yours, may not know about coins you bought elsewhere and may show values in US dollars. The CRA says you must be able to support the cost and value of each transaction, so reconcile the report to your own records.
- Export the full history from every platform you used, since the CRA suggests regular exports because a platform can close.
- Add the purchases made in other places and the coins that came in by transfer.
- Convert each value to Canadian dollars with one method that you can explain.
- Build the running ACB for each coin lot by lot.
- Compare your total proceeds and units with the platform totals. Write down any difference and why.
The CRA books and records page also asks for opening and closing balances with the cost of the opening balance. That opening cost is the ACB you carry from last year. If you cannot rebuild an old cost, tell the CRA or a professional what you do have. We do not give a workaround here.
What mistakes happen with the cost base?
- Leaving out the purchase fee, which makes the gain too high.
- Using the price of the last purchase as the cost of everything you hold.
- Forgetting to reduce the units after a swap or a payment made with coin, which are both dispositions.
- Treating a wallet transfer as a new purchase at today's price.
- Mixing different coins in one average. Each coin has its own ACB.
- Copying US dollar figures straight into the return.
The crypto capital gains examples page has more worked numbers, and the crypto swap page shows how a trade sets the cost of the new coin. For the big picture, see our crypto tax guide.
What is still unknown?
Three things are not settled on a CRA crypto page. First, whether units of one coin are identical properties. Second, how the superficial loss rule, which can deny a loss when you buy the same property back close to the sale, applies to crypto. T4037 lists the topic, but we did not read its text. Third, how to treat fees paid in coin. Ask the CRA or a qualified professional for any of these.
This page is information only. We do not prepare returns, we do not represent the CRA or any organization, we do not guarantee the figures are correct for your case and we are not liable for decisions based on this page. The examples are made up.
Frequently asked questions
What is the ACB of crypto in Canada?
It is the cost of the coin in Canadian dollars plus the expenses of buying it, such as a trading fee. You subtract it from your proceeds, along with selling costs, to find a capital gain or loss. Each type of coin has its own ACB.
Do I average my crypto purchases?
CRA guide T4037 requires averaging for identical properties such as shares of one class. It does not mention crypto, and the CRA crypto pages do not address averaging. Many preparers average units of the same coin. Confirm with the CRA or a professional.
Do fees add to my cost base?
Fees you pay to buy a coin are expenses to acquire it, so they add to the ACB. Fees you pay to sell are outlays of the disposition, so they reduce the proceeds. The CRA guide names commissions as examples of both kinds.
Does a wallet transfer change the ACB?
No. The CRA says transfers between wallets you own are generally not dispositions. The coin keeps the same cost. Keep both wallet addresses and the date in your records so you can show that both wallets are yours and trace each coin.
What happens to my ACB when I sell part of a holding?
The coins you sold use the average cost per unit. The coins you keep stay at the same average per unit. In our example, selling 0.4 of 1 coin removes 40 percent of the total cost and leaves 60 percent on the rest.
What if I do not know the cost of coins I bought years ago?
The CRA says you must keep records of cost and value for six years after the last tax year. If records are missing, we have not read a CRA page that gives a fallback. Collect old exchange statements and ask the CRA or a professional.