Any unused Capital Gains Tax losses from previous years that are carried forward have to be used against the first available capital gains. This means that you can reduce your capital gains to the yearly allowance amount (£12,300 in 2020-21) and carry forward the remaining losses.
TaxCalc does this automatically by applying the annual exempt amount and using the remaining balance against losses that have been brought forward. If there are then any losses remaining, TaxCalc carries these forward and imports them onto next year’s return.
You can read more about what do if you make a loss on the HMRC website.
The following table shows the annual exemption amounts for Capital Gains Tax for previous years.