UK Crypto Tax Deadlines 2025/26: 31 January 2027 and More

The main UK crypto tax deadline for the 2025/26 tax year is 11:59pm on 31 January 2027: that is when your online Self Assessment return must be filed and any Capital Gains Tax and Income Tax paid. Before that come two dates people miss — 5 October 2026 to register for Self Assessment if you have never filed, and 31 December 2026 if you use HMRC's real time Capital Gains Tax service instead of a return. This guide lists every date that matters for crypto in 2025/26, what happens if you miss one, and the deadlines for fixing earlier years.

What are the key crypto tax dates for 2025/26?

The 2025/26 tax year ran from 6 April 2025 to 5 April 2026. Everything you sold, swapped, spent, gifted or earned in that window is reported and paid in the calendar below.

Two related dates for context: the first Cryptoasset Reporting Framework reports from UK crypto platforms, covering 2026 activity, are due to HMRC between 1 January and 31 May 2027; and losses from 2022/23 must be claimed by 5 April 2027.

When is the Self Assessment deadline for crypto?

For 2025/26, HMRC must receive your online return by 11:59pm on 31 January 2027. If you file on paper, the deadline is 11:59pm on 31 October 2026. You can file any time from 6 April 2026, and there is no reason to wait until January: filing early gives you a tax figure to plan for and time to fix any problems with your records.

You need to file a return if you had to pay Capital Gains Tax on a disposal, if you are already in Self Assessment and your total disposal proceeds were over £50,000 (for 2023/24 onwards), if you want to claim a loss, or if you have crypto income above the reporting thresholds. Since the 2024/25 return, the SA108 capital gains pages include a cryptoasset section for your disposals.

When do you need to register for Self Assessment?

By 5 October 2026 for the 2025/26 tax year, if you have not sent a return before or you registered before but did not need to file for 2024/25. GOV.UK says that if you register after 5 October, HMRC will send you a letter or email with a different filing deadline — 3 months from the date on it — but you must still pay any tax you owe by 31 January 2027 or you will get a penalty.

Registering late and paying late can also trigger a "failure to notify" penalty based on the tax still unpaid. If you realise in November that you should have registered, do it immediately; the filing deadline moves but the payment date does not.

What is the real time Capital Gains Tax service deadline?

If you are a UK resident who is not otherwise in Self Assessment and you only have a capital gain to report, you can use HMRC's real time Capital Gains Tax service instead of a full return. GOV.UK says: "You must report by 31 December in the tax year after you made your gain and pay by 31 January." For 2025/26 gains, that means reporting by 31 December 2026 and paying by 31 January 2027.

You have to attach your calculations when you report, HMRC then sends a payment reference starting with "X", and you pay using that reference. Two limits: the service currently covers gains made in 2025/26 and 2026/27, and if you are already registered for Self Assessment you still need to include the gain in your return.

When do you pay crypto tax?

By 11:59pm on 31 January 2027 for 2025/26. Capital Gains Tax is paid as part of your "balancing payment" on that date — GOV.UK confirms the 31 January balancing payment "will also include anything you owe for capital gains". Payment methods with same or next day clearance include online banking (Faster Payments), CHAPS and debit card; Bacs and Direct Debit take 3 to 5 working days, so allow time. You can also make payments in instalments ahead of the deadline through your HMRC online account.

If the 31 January bill includes Income Tax on staking or mining, you may also have to make payments on account towards 2026/27: two instalments on 31 January 2027 and 31 July 2027, each half of your 2025/26 Income Tax bill. You do not have to make them if your 2025/26 bill was under £1,000 or if more than 80% of your tax was collected at source, and you can ask HMRC to reduce them if you expect to owe less. Capital Gains Tax is not included in payments on account.

What happens if you miss the deadline?

Penalties start immediately and grow. GOV.UK lists the late filing penalties: an initial £100, then after 3 months £10 a day up to a maximum of £900, then after 6 months a further 5% of the tax due or £300 (whichever is greater), and after 12 months another 5% or £300. Late payment adds separate penalties of 5% of the unpaid tax at 30 days, 6 months and 12 months.

Interest also runs daily on anything unpaid from 1 February 2027. HMRC's late payment interest rate is set at Bank of England base rate plus 4% (from 6 April 2025), and GOV.UK publishes the current and past rates. If you cannot pay in full, contact HMRC before the deadline about a payment plan — penalties are avoidable if an arrangement is in place, though interest still accrues. If you have a reasonable excuse for filing late, you can appeal a penalty.

What are the deadlines for earlier years?

The Self Assessment deadlines for earlier years have passed, but three routes remain. You can amend a filed return online within 12 months of its filing deadline — so a 2024/25 return can be corrected until 31 January 2027. For older years, you can write to HMRC to report income or gains you left out. And for unpaid crypto tax from earlier years, HMRC's Cryptoasset Disclosure Service lets you disclose voluntarily and pay in one go.

The disclosure service has its own timing rule: after you submit, HMRC sends you a payment reference (allow up to 15 working days) and you must pay within 30 days of submitting. Interest is charged from the original due date of each year's tax — 31 January following the tax year — until you pay, so the sooner you disclose the less it costs. Our disclosure service guide explains how many years you need to include.

How long do you have to claim a crypto loss?

Four years after the end of the tax year in which the loss arose. GOV.UK says you do not have to report losses straight away and can claim "up to 4 years after the end of the tax year that you disposed of the asset". A loss made in 2022/23 must be claimed by 5 April 2027, which makes this January's return the natural place to do it.

Unclaimed losses are lost for good after the four years, and claimed losses carry forward indefinitely to reduce future gains above the annual exempt amount — so it is worth claiming even in a year with no gains. If you have never made a gain and are not registered for Self Assessment, you can write to HMRC instead.

When are the deadlines for crypto income?

The same dates apply: staking, mining and lending income for 2025/26 is reported on the return due 31 January 2027. The thresholds decide whether you need to be in Self Assessment at all — GOV.UK says to contact HMRC if your total miscellaneous income is between £1,000 and £2,500, and to register for Self Assessment (by 5 October 2026) if it is over £2,500.

What should you do now?

If you disposed of crypto in 2025/26, work out your gains now rather than in January. Download your exchange exports while they are still available, calculate each year you need, and check whether you must report. If HMRC has written to you, the response date on the letter is your first deadline — the letter helper will tell you which years to calculate and which route to use.

Sources

• Self Assessment tax returns: deadlines — GOV.UK
• Check how to register for Self Assessment — GOV.UK
• Self Assessment tax returns: who must send a tax return — GOV.UK
• Report and pay your Capital Gains Tax: other capital gains — GOV.UK
• Pay your Self Assessment tax bill — GOV.UK
• Understand your Self Assessment tax bill: payments on account — GOV.UK
• Self Assessment tax returns: penalties — GOV.UK
• Self Assessment tax returns: if you need to change your return — GOV.UK
• HMRC interest rates for late and early payments — GOV.UK
• Capital Gains Tax: if you make a loss — GOV.UK
• Tell HMRC about unpaid tax on cryptoassets — GOV.UK
• Check if you need to pay tax when you receive cryptoassets — GOV.UK
• Check if you need to report cryptoasset data to HMRC — GOV.UK