The UK’s tax, payments and customs authority (HMRC) has launched a calculator for taxpayers affected by the 2024–25 Capital Gains Tax (CGT) rate changes. Those filing tax returns online through HMRC’s service may need to use this tool to determine a CGT “adjustment figure”, as the system will not automatically apply the new main rates where relevant.
This announcement was made by HMRC on 17 March 2025.
The government announced changes to Capital Gains Tax (CGT) rates in the 2024 Autumn Budget. These changes will take effect from 30 October 2024, during the 2024-25 tax year.
Key updates:
- The lower CGT rate will rise from 10% to 18%.
- The higher CGT rate will increase from 20% to 24%.
- The CGT rate for trustees and personal representatives will also go up from 20% to 24%.
- Residential property gains will remain taxed at 18% for basic rate taxpayers and 24% for higher rate taxpayers.
If a taxpayer sells assets before and after 30 October 2024, they will need to calculate gains separately, applying the appropriate CGT rates for each period.
Who should use the calculator
Use the calculator if:
- you have made a disposal of assets on or after the 30 October 2024
- you are completing a Self Assessment tax return for the 2024 to 2025 tax year as an individual, trustee or personal representative
- your overall capital gains are above your tax-free allowance (known as the annual exempt amount)
To use the calculator, taxpayers will need to have the following:
- date of disposal
- amount of gains
- taxable income
- details of any capital losses
- details of any pension schemes or Gift Aid payment
