When crypto creates a CGT event
A capital gain or loss arises whenever you dispose of crypto: selling it for dollars, swapping it for another crypto, spending it on goods, or gifting it. The ATO's guidance is explicit about swaps. Exchanging one crypto asset for another disposes of the first and acquires the second, so a CGT event happens to the original asset. The capital proceeds are the market value, in Australian dollars, of the crypto you receive, or, if you cannot work that out, of the crypto you gave up. Moving crypto between wallets you own is not a disposal.
A worked example
On 1 March 2024 you buy 0.5 BTC for $30,000 plus a $30 fee: a cost base of $30,030. On 10 February 2025 you swap 0.2 BTC for ETH; at that moment the ETH you receive is worth $30,000, and the exchange charges $20.
- Cost base of the 0.2 BTC disposed of: 0.2 ÷ 0.5 × $30,030 = $12,012.
- Capital proceeds: $30,000 − $20 = $29,980.
- Capital gain: $17,968, in 2024–25.
- Held from 1 March 2024 to 10 February 2025, under 12 months, so no discount. The full $17,968 is added to taxable income.
- The ETH you received starts a new parcel with a cost base of $30,000 on 10 February 2025.
Enter the swap as a sale of 0.2 BTC at $150,000 per BTC (the AUD value per unit) with the $20 fee, and a buy of the ETH at its AUD value. The remaining 0.3 BTC keeps its original date and cost base.
How the calculation works
- Capital proceeds. What you received for the asset, less selling costs such as brokerage or the agent's commission.
- Cost base. What it cost you: the purchase price plus incidental costs of buying it (brokerage, stamp duty, legal fees), and for property, capital improvements.
- Gain or loss. Proceeds minus cost base, for each parcel sold.
- Losses. Capital losses carried forward from earlier years and losses made this year are taken off this year's gains. The ATO says you can choose which gains they reduce; taking them off gains that do not get the discount first gives the lowest result, and that is what the calculator does.
- Discount. Australian-resident individuals halve what is left of each gain on an asset owned for at least 12 months, counting from the day after acquisition to the day before the CGT event.
- Net capital gain. The total goes in your tax return and is taxed at your marginal rate along with your other income. A net capital loss cannot reduce other income; it carries forward.
Exchange CSVs
CoinSpot, Swyftx, Binance and Kraken exports are recognised by their headings; others can be mapped by hand. Exchange exports often quote prices in the pair's currency (for example BTC/USDT). The calculator needs AUD values, so convert those rows before importing, or edit the price after import. Check every swap appears as a sale and a matching purchase.
Matching parcels
Crypto is fungible, so most people use first in, first out. The ATO accepts other methods where your records identify which units were disposed of; specific identification is mostly practical when different holdings are kept in different wallets. Whatever you choose, apply it consistently and keep the records.
Record keeping
Keep, for every transaction: the date, the AUD value, what it was for, the other party (exchange or wallet address), and exchange records and wallet addresses. Exchanges close and data disappears; download your history at least once a year.
Checking the result before you lodge
A calculator is only as good as the figures you give it. Before copying anything into your tax return, run through these checks:
- Holdings reconcile. The units left over after every sale should match what your broker, share registry or exchange says you still hold. If they do not, a buy, DRP or split is missing, and the cost base of some sale is wrong.
- Dates are trade or contract dates. Settlement dates move sales across 30 June and across the 12-month mark.
- Costs are on the right side. Purchase costs belong to the buy; selling costs belong to the sale. Entering both on one side gives the same gain but the wrong cost base for the parcels that are left.
- Losses brought forward match last year's return. The figure at label V of last year's return is this year's starting point.
- Pre-filled data. The ATO pre-fills some share and crypto data from brokers and exchanges. It often lacks cost bases, so treat it as a list of sales to account for, not as the answer.
If a disposal looks wrong, open its parcel breakdown in the year view: each line shows the parcel, its acquisition date, days held and cost base, which is usually enough to spot the missing or mistyped transaction.
Where the rules come from
The discount, the 12-month counting rule, the treatment of losses and the tax rates are taken from the ATO's published guidance, listed under sources below with the date they were last checked. Rates are stored per financial year and updated each July. Where a rule could not be confirmed against an official page, it is marked as unverified in the calculator's notes and in the schedule, so you and your accountant know what to check.
Lost, stolen and scammed crypto
If you lose the private key to a wallet, or an exchange collapses, you may be able to claim a capital loss, but only with evidence: when you acquired the crypto and what it cost, the wallet address, that it belonged to you, and that it cannot be recovered. Crypto sent to a scammer is treated similarly. Record these as sales with zero proceeds and keep the evidence with your records; the ATO may ask for it.