$BTC | If you missed the 30 June window to harvest a crypto loss in Australia, is the deduction gone?
No. A realised capital loss on crypto does not expire. If you did not sell an underwater position before 30 June 2026, you lost the chance to offset gains in the 2025-2026 year specifically, not the loss itself. Under section 102-15 of the ITAA 1997, any loss you do realise carries forward indefinitely until you have gains to use it against.
This matters right now because the calendar is confusing people. The 31 October deadline sitting ten days out is a lodgment deadline for the 2025-2026 return, not a second chance at tax-loss harvesting for that year. On the desk we used to get this exact question from junior traders every October: "can I still do something about last year's tax." For ordinary income the answer is almost always no once the year has closed. For capital losses, the answer is more useful than that, and most retail crypto holders do not realise it.
## Why the 30 June window closing does not erase the loss
Tax-loss harvesting in Australia works in a fixed order. You realise a loss by disposing of a position (selling to AUD, swapping to another token, gifting it, or sending it somewhere you no longer control), then that loss nets against capital gains realised in the same financial year, and only the remaining net gain gets the 50 percent CGT discount if held over 12 months. If 2025-2026 is already closed and you never disposed of the losing position, you have not harvested anything yet. Nothing has crystallised. The loss is still sitting unrealised on your balance sheet, and whether to realise it now is a decision for 2026-2027, not a missed deadline for 2025-2026.
Where people do lose the benefit is a different mistake entirely: selling at a loss and buying the same coin straight back with no real change in position. The ATO does not need a US-style wash-sale rule to catch that; it has Part IVA, the general anti-avoidance provision, and a sell-and-instant-rebuy pattern is close to the textbook example of what it targets.
## What the ATO actually lets you carry forward
Once a loss is realised, there is no cap and no time limit on carrying it forward. SatoshiMacro's tax-loss harvesting calculator models this directly: enter unrealised losses against this year's realised gains and it outputs the carryforward balance alongside the immediate tax saved. Take a trader with AUD 8,000 of short-term gains already locked in and AUD 25,000 of unrealised losses on positions they are exiting anyway. Harvesting now fully offsets the AUD 8,000 (saving roughly AUD 2,400 at a 30 percent marginal rate) and leaves AUD 17,000 to carry into next year. That carryforward balance is not a consolation prize. It sits on the tax account at full value until a future gain consumes it.
## The case with zero gains this year is the one people get wrong
Say there are no realised gains at all in 2025-2026, just AUD 12,000 of losses on positions already decided against. Harvesting produces no saving this year, full stop, because a capital loss can only reduce capital gains, never salary or other ordinary income. But if a large long-term gain is expected later, say when a long-held BTC position eventually gets sold, that AUD 12,000 carries forward and applies before the 50 percent discount, before marginal rate. My read is that the "no current benefit" framing is what stops people from harvesting a position they already want out of. The benefit is deferred, not absent, and an unrealised loss costs nothing to wait on either way.
## Where the calculator's estimate is honest about its own limits
The tool treats all of a year's gains as one cohort matching a single holding-period selection, long-term or short-term. Real portfolios usually mix both, and the ATO's actual ordering rule applies losses against non-discounted gains first because they are taxed at the full rate. That means a real mixed portfolio will equal or beat the calculator's estimate, never fall short of it. It is a planning tool, not a lodgment-ready number, and SMSF holders need the separate SMSF calculator since fund-level gains sit at 15 percent in accumulation phase with a one-third discount rather than the individual 50 percent rate.
## What I would actually do with 10 days to 31 October
Lodge the 2025-2026 return on what already happened; do not try to retrofit a harvest into a year that is closed. Then use the next eight months properly: track unrealised losses as they appear rather than waiting for a May scramble, and keep the recordkeeping clean. ATO record-keeping rules run five years from lodgment, covering date, AUD value, counterparty and fees for every disposal, loss or gain. That discipline is what makes next year's harvest decision a five-minute calculation instead of a guess.
One more thing worth flagging before 31 October: a crypto-to-crypto swap is a disposal in its own right. Swapping ETH for SOL, or USDC for a different stablecoin, can realise a loss (or a gain) without ever touching AUD. If any of this year's swaps sat on a loss versus your AUD cost base at the time, that loss should already be in this return, not next year's. It is an easy one to miss when nothing ever hit a bank account.
Full methodology, the worked examples above, and the Part IVA detail live on SatoshiMacro's calculator page.
https://satoshimacro.com/tools/crypto/calculators/tax-loss-harvesting-calculator/?utm_source=binance_square&utm_medium=social&utm_campaign=autopilot_article