Capital Gains Tax deadlines for property sales remain one of the most critical compliance areas for UK landlords in 2026. Miss these dates and you face automatic penalties that can quickly escalate into significant costs.

The dual reporting system for property CGT creates confusion for many investors. You have both immediate reporting requirements and annual payment deadlines to manage simultaneously.

The 60-Day Reporting Rule

When you sell a UK residential property in 2026, you must report the disposal within 60 days of completion. This applies regardless of whether you owe any CGT.

The 60-day clock starts ticking from your completion date, not exchange. For example, if you complete on a BTL property sale on 15 March 2026, your report and any CGT payment are due by 14 May 2026.

You report through the government's online service and pay any CGT due at the same time. There's no option to defer this payment until your Self Assessment return.

What Triggers the 60-Day Rule

  • Sales of UK residential property (including BTL properties)
  • Disposals of commercial property worth over £2 million
  • Gifts of property above the annual exemption
  • Transfers to connected parties below market value

The rule doesn't apply to your main residence (covered by Principal Private Residence relief) or property transfers between spouses.

Annual Self Assessment Deadlines

Property disposals must also be reported on your Self Assessment return, even if you've already filed the 60-day report. This creates a dual reporting requirement that catches many landlords off guard.

For the 2025/26 tax year, your Self Assessment deadline is 31 January 2027. Any additional CGT not paid within the 60-day window becomes due on this date.

If your initial CGT calculation was incorrect, you'll either receive a refund or need to pay the balance by the Self Assessment deadline.

Key Dates for 2026 Property Sales

Here are the critical deadlines for property disposals in the 2025/26 tax year:

  • 60 days from completion: Report disposal and pay CGT
  • 31 January 2027: Self Assessment return filing deadline
  • 31 January 2027: Any additional CGT payment due
  • 31 July 2027: Second payment on account (if applicable)

Payment on account requirements apply if your CGT liability exceeds £1,000 and represents more than 20% of your total tax bill.

Penalty Structure for Late Compliance

The penalty system for missed CGT deadlines is automatic and escalates quickly. Understanding these costs helps emphasise why timely compliance matters.

60-Day Report Penalties

  • Up to 3 months late: £100 fixed penalty
  • 3-6 months late: Additional £300
  • 6-12 months late: Further £300
  • Over 12 months: Up to 100% of the tax due

Late payment interest runs from the original due date at current rates (7.75% as of 2026).

Self Assessment Penalties

Separate penalties apply for late Self Assessment filing, starting at £100 and escalating to daily penalties after three months.

Calculating Your CGT Liability

CGT rates for 2025/26 remain at 18% and 28% for residential property, depending on your total income. The annual exemption is £3,000 per person.

For example, a higher-rate taxpayer selling a BTL property with a £50,000 gain pays £14,000 CGT (28% rate) minus the £3,000 exemption, resulting in £13,160 due.

Our calculators can help estimate your liability, though complex scenarios require professional advice to ensure accuracy.

Planning Around Deadlines

Smart timing of property sales can help manage cash flow around CGT deadlines. Consider completing sales early in the tax year to maximise time between payment and your next Self Assessment deadline.

Alternatively, completing near the tax year end gives you longer before the following year's payment on account falls due.

For portfolio landlords with multiple disposals, spreading sales across tax years can help manage the administrative burden and cash flow impact of CGT payments.

Record Keeping Requirements

HMRC expects detailed records supporting your CGT calculations. Keep all documents for at least five years after the filing deadline.

Essential records include purchase contracts, improvement invoices, legal fees, estate agent costs, and evidence of any reliefs claimed.

Digital records are acceptable, but ensure they're backed up and easily accessible if HMRC queries your return.

Getting Professional Support

CGT calculations for property can be complex, particularly with multiple disposals, incorporation decisions, or unusual transaction structures. The dual deadlines create additional compliance pressure.

Getting specialist advice early in the disposal process helps ensure accurate calculations and timely compliance. Our services include CGT planning and compliance support for property investors.

Don't leave CGT compliance to chance. Missing deadlines creates immediate penalties and ongoing interest charges that erode your property profits unnecessarily.