Tax Loss Harvesting Calculator

Tax loss harvesting means strategically selling investments at a loss to offset capital gains, reducing your CGT liability. Unlike the US, UK rules do not have a wash sale restriction but have the 30-day bed and re-buying rule.

Yes. The 30-day rule (bed and re-buying) means if you sell a loss-making investment and rebuy the same asset within 30 days, the loss cannot be used. You must wait 30+ days or buy a different asset.

Yes. Crypto losses can be harvested just like investment losses. Selling crypto at a loss and using it to offset crypto or other capital gains is entirely legal.

The CGT annual exempt amount is £3,000 for 2025/26. Gains up to this amount are tax-free each year.

Yes. If you have more losses than gains in a tax year, the excess losses are carried forward and can be used against future gains. There is no time limit.

Any capital asset — shares, funds, crypto, second properties, collectibles. ISA investments cannot generate CGT losses (but also don't create taxable gains).

Losses must first be used against gains in the same tax year (even if it would bring gains below the allowance). Only excess losses carry forward.

Yes, it is entirely legal tax planning. HMRC's rules on capital losses are designed to allow loss relief. Only the 30-day rule restricts same-asset rebying.

CGT losses can be carried forward indefinitely but cannot be carried back. Income tax losses have different carry-back rules.

The UK tax year ends 5 April. Losses must be realised before 5 April to count in that tax year. You cannot backdate disposals.

Selling to your spouse to realise a loss is a connected person transaction — it is treated as taking place at market value, not the transaction price, so it doesn't create a loss for tax purposes.

Report losses on your Self Assessment return (SA108). You must claim losses within 4 years to use them. Losses do not automatically carry forward without being reported.