If you sell assets such as shares or land, you may need to report your Capital Gains Tax either through Self-Assessment or HMRC’s ‘real time’ CGT service; deadlines and rates depend on the type of asset sold.

If you have Capital Gains that are not related to the sale of UK residential property after 6 April 2020, there are two main ways to report them. The first is by filing a self-assessment tax return or using the ‘real time’ Capital Gains Tax (CGT) service. Before reporting, you must determine if you need to pay tax and how much you owe.

For reporting in a self-assessment tax return, you will include your Capital Gains for the tax year after you sell or dispose of an asset. You can seek help from an accountant or tax advisor, and after submission, HMRC will provide details on how and when to pay.

Alternatively, the ‘real time’ CGT service allows you to report gains from assets sold during the 2024-2025 or 2025-2026 tax years. This service is only available to UK residents and cannot be used for certain items like UK residential property gains or foreign tax credits.

After reporting, HMRC will issue a payment reference number (starting with ‘X’), which you can use for payments via online banking, cheque, or the online tax payment service. You must report your gain by 31 December in the tax year following the gain and pay by 31 January. For example, if you made a gain in the 2024-25 tax year, you need to report it by 31 December 2025 and pay by 31 January 2026.

The main CGT rates for assets other than residential property and carried interest is currently 18% for Income Tax basic rate payers and 24% for Income Tax higher rate payers.

If you sell UK residential property not covered by the Private Residence Relief, for example, a second home, then you must report the sale with a calculation of any CGT due, within six months of completing the sale. HMRC have set up a separate filing process to report these gains.