UK Property

What happens if I miss the 60-day CGT deadline?

Answered by Jordan Onraet-Wells, Founder & Chartered Tax Adviser (CTA). Published 17 July 2026. Last reviewed 17 July 2026.

The short answer

HMRC charges an automatic £100 penalty as soon as your 60-day Capital Gains Tax property return is late, even if no tax is due. If the return is 6 months late you pay a further £300 or 5% of the tax due, whichever is higher, and the same again at 12 months. Interest also runs on any unpaid CGT from the day after the deadline. If you have already missed it, file now: the charges escalate with time, so acting quickly caps the damage.

A £100 fixed penalty applies automatically the day the return is late, even at nil gain or a loss.
At 6 months late HMRC adds £300 or 5% of the tax due, whichever is higher, and the same charge repeats at 12 months.
Interest runs on unpaid CGT from the day after the 60-day deadline until you pay.
The 60-day clock runs from the completion date, not exchange of contracts.
Non-residents must file for every disposal of UK property or land, including losses, nil gains and sales already covered by Self Assessment.
Reasonable excuse is a narrow escape route: living abroad or not knowing the rule rarely qualifies.

The penalty escalates the longer you wait

The £100 fixed penalty lands automatically, whether or not any tax was due. Once the return is 6 months late, HMRC adds £300 or 5% of the tax due, whichever is higher, and charges the same again at 12 months. On a large gain those percentage-based charges dwarf the £100 because they scale with the tax. Interest runs separately on any unpaid CGT from the day after the 60-day deadline until the day you pay, so filing and paying are two halves of the same deadline.

The common trap: nil gain does not mean no return

Non-residents must report every disposal of UK property or land within 60 days of completion, even with no tax to pay, a loss, or a gain fully covered by Private Residence Relief, and even if already registered for Self Assessment. A UK resident only files the 60-day return when tax is actually due. So a seller abroad whose gain is fully relieved still collects the £100 penalty for missing the deadline, with the 6 and 12 month charges to follow. The full mechanics, with worked examples, are in our 60-day CGT rule for non-residents guide.

What to do if you have already missed it

File now to stop the escalation: the penalties are staged, so a return filed 4 months late still avoids the 6 and 12 month charges entirely. Report through HMRC's Capital Gains Tax on UK property account, which non-residents can set up without a National Insurance number, or have an agent file for you, then pay using the reference HMRC issues so interest stops running. If you are in Self Assessment, the disposal also goes on your annual return, where the figures are reconciled; our CGT for non-residents guide covers the wider regime.

Go deeper

Sources and further reading

This is general information for the 2026/27 UK tax year, not personal tax advice; speak to a Chartered Tax Adviser about your own position.

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