CGT is calculated automatically from the buys and sells you log against each investment or crypto holding.
How cost basis is calculated
CeeWealth pools purchases of the same asset using the same Section 104 logic HMRC applies, rather than tracking each purchase as a separate lot. When you sell, your gain is calculated against that pooled average cost.
The 30-day rule
If you sell and rebuy the same asset within 30 days, HMRC's "bed and breakfasting" rule changes which cost basis applies. Log both transactions as they happen so this is factored in correctly, rather than trying to correct it after the fact.
Checking your exposure before you sell
Your portfolio view shows unrealised gains per holding, so you can see roughly what a sale would cost in CGT before you make it - useful for deciding whether to harvest gains before the tax year ends.
Where it shows up
All realised gains and losses for the current tax year appear in the tax year report, tracked against your Annual Exempt Amount automatically.