Offsetting overpaid CGT
Many people are looking to file their tax return early for 2020/21. However, an issue has come to light where a 30-day capital gains tax (CGT) return has also been filed during the year. What’s the issue and the solution?
Since April 2020 anyone who makes a chargeable gain on a UK residential property where there is a tax bill must report the gain and pay an estimate of the tax to HMRC within 30 days of completion. This tax return requires the seller to estimate their income in order to apply the appropriate rate of CGT. The actual level of income is often not known until the end of the tax year. In light of the pandemic, it’s easy to see how someone filing a 30-day CGT tax return might have assumed all the gain would be taxed at 28%, but on reflection some is taxable at 18% instead. More information about 30-day reporting is available here.
As the gain must also be reported on the self-assessment tax return, it seems reasonable to assume that any overpayment would be sorted out once the return is filed. However, it transpires that HMRC’s computer system does not offset the overpaid amount automatically. In order to get the tax offset, there are two options:
- amend the 30-day return to correct the amount before the tax return is filed. This sorts out the overpayment, albeit separately to the main tax return;
- or if the return has already been filed, contact HMRC directly to request a manual offset. The problem is known to HMRC’s officers and so should be done swiftly. This can be done by the taxpayer, or by their accountant or tax advisor.
Note. An amendment cannot be made due to losses that were realised later on in the tax year, even if these absorb the gain in full. In these circumstances, requesting a manual offset will be the only option.
Related Topics
-
Sharing salary with your partner
You’re a director with a substantial salary and your partner isn’t working right now. If you could split your salary with your partner the tax saving would make a real difference. How can you legitimately share your salary to improve the overall tax position?
-
HMRC bungles 2026/27 PAYE codes for pensioners
For some pensioners, the 2025/26 winter fuel payment should be collected via their 2026/27 PAYE code. HMRC has started to issue PAYE codes for the new tax year, but the extra charge is missing. What's going on?
-
Are you including too much income in your calculations?
Your business is partly exempt and you claim input tax on your mixed costs and general overheads by using the standard method based on turnover splits. What income should you exclude from the calculations?


This website uses both its own and third-party cookies to analyze our services and navigation on our website in order to improve its contents (analytical purposes: measure visits and sources of web traffic). The legal basis is the consent of the user, except in the case of basic cookies, which are essential to navigate this website.