Report Capital Gains Tax: How to Report and Pay CGT to HMRC in 2026/27

Report Capital Gains Tax correctly is essential when you sell or dispose of assets that have increased in value. Whether you have sold shares, investments, land or property, understanding the reporting process helps ensure you meet HMRC requirements and avoid unnecessary penalties.

Capital Gains Tax (CGT) reporting depends on the type of asset disposed of and whether you have a requirement to file a Self Assessment tax return. Some gains can be reported through HMRC’s online services, while others must be included within your annual tax return.

Before you report CGT to HMRC, you need to calculate your gain, check whether any exemptions or reliefs apply and determine whether tax is payable. Whether tax is due also depends on your wider Income Tax position, explained fully in our ultimate guide to personal tax in the UK.

This guide explains how Capital Gains Tax reporting works, the relevant deadlines, how to pay Capital Gains Tax and what taxpayers need to do when disposing of different types of assets.

When Do You Need to Report Capital Gains Tax?

You may need to report Capital Gains Tax when you dispose of an asset that creates a taxable gain.

Common assets that may require CGT reporting include:

• Shares and investment funds.
• Buy-to-let properties.
• Second homes.
• Business assets.
• Land and other chargeable assets.

You do not normally pay CGT where the gain is fully covered by exemptions or reliefs, such as Private Residence Relief on a qualifying main home.

However, even where no tax is payable, reporting requirements may still apply depending on your circumstances.

How to Report CGT to HMRC

The method used to report Capital Gains Tax depends on the asset sold and your personal tax position.

Generally, individuals report gains through one of the following methods:

• Self Assessment tax return.
• HMRC’s Capital Gains Tax online service for eligible disposals.
• Property-specific reporting service for UK residential property disposals.

Before submitting any report, you should calculate:

• The disposal proceeds.
• The original acquisition cost.
• Allowable expenses.
• Available capital losses.
• Any applicable reliefs.
• The final taxable gain.

A full walkthrough of how to work out capital gains step by step can help ensure none of these figures are missed before you submit a report to HMRC.

Keeping accurate records makes the reporting process easier and helps support your figures if HMRC requests further information.

Reporting Capital Gains Through Self Assessment

Many taxpayers report CGT through their Self Assessment tax return.

This usually applies where you:

• Already complete a Self Assessment return.
• Have taxable capital gains that need reporting.
• Need to report gains alongside other income sources.

When completing your tax return, you must include details of your capital gains for the relevant tax year.

HMRC will calculate the tax due based on the information provided, including your income position, available allowances and applicable CGT rates.

If you are unsure how to complete the calculation or which reliefs apply, professional advice can help ensure the return is accurate.

Using HMRC’s Capital Gains Tax Service

HMRC provides an online service that allows eligible individuals to report certain capital gains separately from Self Assessment.

This service may be useful for taxpayers who have made gains from assets such as:

• Shares.
• Investments.
• Other qualifying chargeable assets.

The rules for what happens when you sell shares specifically are worth reviewing in more detail, since the reporting route can differ from other chargeable assets.

However, the service is not available for every type of disposal and does not remove the requirement to file a Self Assessment return where one is needed.

Taxpayers should check which reporting method applies based on the asset sold and their individual circumstances.

Capital Gains Tax Deadline for Non-Property Assets

The Capital Gains Tax deadline depends on how the gain is reported.

For most non-property disposals, taxable gains are normally reported through Self Assessment after the end of the relevant tax year.

The usual deadlines are:

• Submit your online Self Assessment tax return by 31 January following the end of the tax year.
• Pay any CGT due by 31 January following the tax year in which the gain occurred.

For example, gains made during the 2026/27 tax year would normally be reported through Self Assessment by 31 January 2028, with payment also due by that date.

Reporting and Paying CGT on UK Property

Different rules apply when selling UK residential property that creates a Capital Gains Tax liability.

If you sell a UK residential property that is not fully covered by Private Residence Relief, you normally need to:

• Report the gain to HMRC within 60 days of completion.
• Pay the Capital Gains Tax due within the same timeframe.

This applies to properties such as:

• Buy-to-let properties.
• Second homes.
• Inherited residential properties.
• Holiday homes.

The 60-day reporting requirement applies separately from the annual Self Assessment deadline.

How to Pay Capital Gains Tax

Once HMRC has received your CGT report, you need to arrange payment of the tax due.

Payment methods may include:

• Online banking.
• HMRC’s online payment service.
• Other approved payment methods.

When paying, you must use the correct payment reference so HMRC allocates the payment to your tax account correctly.

Late payment may result in interest charges and additional costs.

Capital Gains Tax Rates for 2026/27

The amount of CGT payable depends on the type of asset sold and your income position. Our full reference guide to current rates and allowances covers this in more detail alongside the Annual Exempt Amount.

Your taxable income affects whether your gain falls within the basic-rate band or is charged at the higher CGT rate.

Records Needed for Capital Gains Tax Reporting

Maintaining proper records is an important part of accurate Capital Gains Tax reporting.

You should keep records including:

• Purchase documents.
• Sale agreements.
• Professional fees.
• Improvement costs.
• Broker statements.
• Evidence of capital losses.

These records help support your calculation and ensure you claim all available deductions correctly.

Common Mistakes When Reporting CGT

Common mistakes include:

• Missing the 60-day property reporting deadline.
• Using outdated CGT rates.
• Forgetting allowable costs.
• Failing to claim available losses.
• Reporting gains in the wrong tax year.
• Assuming all property sales are exempt.

Errors can result in incorrect tax payments, HMRC enquiries and potential penalties.

Example: Reporting a Capital Gain

John sells shares during the 2026/27 tax year.

The details are:

• Sale proceeds: £80,000.
• Original purchase cost: £50,000.
• Allowable costs: £2,000.

The calculation is:

• Capital gain: £28,000.
• Less Annual Exempt Amount: £3,000.
• Taxable gain: £25,000.

John reports the gain using the appropriate HMRC reporting method and pays the CGT due based on his income tax position.

Key Takeaways

Knowing how to report Capital Gains Tax helps taxpayers meet their HMRC obligations and avoid unnecessary penalties.

The correct Capital Gains Tax deadline depends on the type of asset sold. Residential property disposals generally require reporting and payment within 60 days, while other gains are usually dealt with through Self Assessment where required.

Accurate calculations, proper record keeping and timely reporting ensure that taxpayers pay the correct amount of CGT while making use of available allowances and reliefs.

Case Study: Avoiding HMRC Issues When Reporting Capital Gains

Sarah visited our Farringdon office after selling a buy-to-let property and wanted support with the Capital Gains Tax reporting process. She was unsure about the correct HMRC deadline, which expenses could be deducted and whether she needed to report the gain through Self Assessment or HMRC’s separate Capital Gains Tax service.

During the consultation, we reviewed Sarah’s property records, purchase documents, sale information and related costs to prepare an accurate CGT calculation before submission. We explained how to report Capital Gains Tax to HMRC, including the difference between residential property reporting within 60 days of completion and reporting other taxable gains through Self Assessment where required. We also reviewed available allowances, allowable costs and the importance of keeping supporting evidence for professional fees, improvements and transaction records.

Following the review, Sarah understood her Capital Gains Tax deadline, the correct reporting method for her disposal and the steps needed to pay the correct amount of tax. By addressing the reporting requirements before submission, she was able to meet HMRC obligations confidently and reduce the risk of avoidable errors or penalties.