To file a CGT return on UK property, work out your gain from the sale price, base cost and allowable costs, deduct any reliefs and your £3,000 annual exempt amount, then report it through HMRC’s Capital Gains Tax on UK property account and pay the tax within 60 days of completion. If you file Self Assessment, you also include the sale on your annual return, and the tax already paid is credited.
The process takes most sellers an hour or two once the figures are ready, but mistakes with dates, costs or reliefs are common and can mean paying too much or facing penalties. HMRC’s own guide to reporting and paying Capital Gains Tax is the starting point.
This step-by-step guide walks through filing a CGT return on UK property in 2026/27, with a worked example, the most common errors and what happens after you file.
Do You Need to File a CGT Return on UK Property?
You must file a CGT return on UK property within 60 days of completion if:
- You are UK resident and there is CGT to pay on a UK residential property, such as a second home, buy-to-let or inherited property.
- You are not UK resident and you sold or disposed of any UK property or land, even if there is no tax to pay.
You do not need to file one if the gain is fully covered by Private Residence Relief, your annual exempt amount or losses. See our guide to the 60-day capital gains tax rule.
Step-by-Step: Filing a CGT Return on UK Property
Step 1: Gather your documents
You will need the purchase and sale completion statements, the exchange and completion dates, receipts for improvements, and the probate valuation if you inherited the property. Our guide to capital gains tax records lists what to keep.
Step 2: Calculate the gain
Take the sale price, or market value for a gift, and deduct the purchase price or probate value, purchase costs such as Stamp Duty and legal fees, selling costs such as estate agent fees, and capital improvement costs. See which costs reduce CGT.
Step 3: Apply reliefs and your allowance
Deduct any Private Residence Relief for the periods the property was your home, any losses, and your £3,000 annual exempt amount. Joint owners each calculate their own share. See CGT on jointly owned property.
Step 4: Estimate your income and rate
Estimate your taxable income for the tax year. Gains within your unused basic rate band are taxed at 18% and the rest at 24%. Our guide to CGT rates for 2026 explains the bands.
Step 5: Sign in to your UK property account
Sign in to HMRC’s Capital Gains Tax on UK property account, or create one if this is your first sale. Our guide on what a UK property account is explains the set-up.
Step 6: Enter the details and submit
Enter the property address, acquisition date, exchange and completion dates, values, costs, reliefs and your income estimate. Check the calculation HMRC shows before you submit.
Step 7: Pay the tax within 60 days
Use the payment reference to pay by online banking, bank transfer, debit or corporate credit card, or cheque. HMRC’s page on ways to pay Capital Gains Tax lists the options.
Step 8: Include the sale on your Self Assessment return
If you file Self Assessment, report the gain again on your return by 31 January after the tax year ends. The 60-day payment is credited, and any difference is collected or refunded.
Worked Example: Filing a Return for a Second Home
Helen sells a holiday cottage, exchanging on 2 November 2026 and completing on 20 November 2026 for £310,000. She bought it in 2016 for £220,000, with £6,000 of purchase costs, spent £14,000 on an extension, and paid £5,500 in selling costs. Her taxable income for 2026/27 is £60,000, so she is a higher rate taxpayer.
| Line | Amount |
|---|---|
| Sale price | £310,000 |
| Less purchase price | (£220,000) |
| Less purchase costs | (£6,000) |
| Less extension (improvement) | (£14,000) |
| Less selling costs | (£5,500) |
| Gain | £64,500 |
| Less annual exempt amount | (£3,000) |
| Taxable gain | £61,500 |
| CGT at 24% | £14,760 |
Helen must file her CGT return on UK property and pay £14,760 by 19 January 2027, 60 days after completion, then include the sale on her 2026/27 Self Assessment return by 31 January 2028. You can estimate your own figures with our property CGT calculator.
Common Mistakes When Filing
- Using the wrong date. The tax year is set by the exchange date, but the 60-day deadline runs from completion.
- Claiming repairs as improvements. Only capital improvements reduce the gain.
- Forgetting the annual exempt amount or claiming it twice where other gains were made in the same year.
- Underestimating income, which leaves extra tax to pay through Self Assessment.
- Joint owners filing one return. Each owner reports their own share.
- Missing the deadline. A £100 penalty applies straight away, with more after six and twelve months. See our guide if your CGT deadline was missed.
What Happens After You File
HMRC may check your return and ask for evidence of costs or reliefs. You can amend your own return in your UK property account, except for 2023 to 2024 or earlier, or once your Self Assessment return for the same year has been filed. Keep all documents for at least four years after the end of the tax year. If you would rather not file yourself, our CGT returns service handles the whole process.
Frequently Asked Questions
How do I file a capital gains tax return for UK property?
Calculate the gain, apply reliefs and your annual exempt amount, then report it through HMRC’s Capital Gains Tax on UK property account and pay within 60 days of completion.
What information do I need to report CGT on a property sale?
The property address, purchase and sale dates and values, exchange and completion dates, buying, selling and improvement costs, any reliefs, and an estimate of your income for the year.
Can I file a CGT return on UK property by post?
Yes, if you cannot use the online service. You complete HMRC’s online form, print it and post it, and HMRC sends you a payment reference.
Do I file a CGT return if I sold my home?
Not if Private Residence Relief covers the whole gain. If part of the gain is taxable, for example because you let it out, you must report within 60 days.
Do both joint owners need to file?
Yes. Each owner files their own return for their share of the gain and uses their own annual exempt amount.
Can someone file the return for me?
Yes. An accountant can file through their agent services account once you authorise them, and someone with power of attorney can report using their own account.
Conclusion
Filing a CGT return on UK property is manageable if you follow the steps: gather documents, calculate the gain, apply reliefs and your allowance, estimate your income, then report and pay through your UK property account within 60 days of completion.
Double-check dates and costs, and remember the sale also goes on your Self Assessment return.
For help filing your CGT return on UK property, speak to our capital gains tax specialists. Call us on +44 (0)1204 859315 or send us your question for a free initial consultation and a fixed-fee quote within 24 hours.
