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UK Tax

What to do if you missed the UK tax deadline

Find out the steps to take if you missed the UK crypto tax deadline and want to avoid and minimise penalties.

Samantha Adams

Samantha Adams

Wed Feb 01 2023

First published: 12 Feb 2020. Most recent update: 01 Feb 2023

HMRC has revealed that a record 11.7 million customers filed their tax return for the 2021 to 2022 tax year by 31 January, with 36,767 filing in the last hour. More than 12 million customers were expected to file a Self Assessment. If you’re one of the estimated 600,000 who missed the deadline then keep reading.

I missed the tax deadline – what should I do now to avoid late filing penalties from HMRC?

To achieve the minimum penance possible you need to file your tax return and pay your tax bill as soon as possible. We can’t turn back the clock, so let’s stop panicking and start filing! Remember that sometimes a late tax return is better than a rushed and incorrect one.

1. Calculate your crypto tax

Most likely you’ll be liable for capital gains tax on profits from selling or trading your cryptocurrency, income taxes can also apply for activities like mining and rewards from staking.

It’s important to keep accurate records of all of your crypto transactions as calculating your cryptocurrency capital gains tax involves determining the value of your cryptoassets as of the date you acquired them and the date you sold or traded them. Intro – Recap

If you are unsure of how to calculate your crypto tax we recommend using a crypto tax calculator like Recap to simplify things.

2. File your tax return via the Government Gateway

The easiest way to file your taxes with HMRC is online - simply sign in to the Government Gateway. To make things less of a scramble, try gather everything you will need to hand, including your unique taxpayer reference (UTR).

If you’re not already registered for self assessment, you can register here. You’ll need your UTR and activation code to start filing, as HMRC send these by post you may have to wait up to 10 days before you can log in.

Carefully fill in your tax return. Use your Recap tax report to file your capital gains on form SA108 and any income on SA100. For more detail head to our blog How to file your crypto taxes with HMRC.

3. Pay your tax bill

Funnily enough, HMRC make paying your tax bill very accessible. There are three different ways to pay:

  • Online - you can pay your taxes online by debit or credit card.
  • Bank Transfer - by using online or telephone banking. It usually takes up to 3 working days for your payment to reach HMRC.
  • Cheque - you can send a cheque by post, just ensure you fill it in correctly and write your 14-digit Capital Gains reference number (starting with X) on the back.

If you’re worried about being able to afford the tax due, you may be able to set up a payment plan by logging into your Government Gateway account or by contacting HMRC’s Payment Support Service. We recommend contacting them as soon as possible to avoid further penalties and unnecessary stress.

What are the penalties from HMRC for filing my tax return late?

There are different costs, penalties are dependent on how late you file…

  • File up to 3 months late: you’ll get a fixed penalty of £100
  • More than 3 months late: you’ll be charged £10 a day (up to £900)
  • After six months: HMRC will fine you £300, or charge 5% of the tax you owe, whatever is larger.

You will also face interest on the tax that you owe. You can use HMRC’s online calculator to estimate how much you may need to pay.

Can I appeal a HMRC penalty for late filing?

Anyone with a legitimate excuse for missing the tax deadline can talk to HMRC to avoid fines. Those with genuine excuses will be treated leniently as HMRC try to focus penalties on repeat offenders and tax evaders, however they may ask you to provide evidence to prove your case.

What’s a valid excuse for missing the self assessment tax return deadline?

HMRC showed their softer side when they shared some of the weirdest excuses they’ve received (obviously they were not accepted)…


Below are some of the reasonable excuses HMRC may accept; normally unexpected events that fall out of your control and occur close to the deadline preventing you from filing your tax return.

Legitimate excuses for appealing a HMRC tax penalty:

  • A serious or life-threatening illness
  • Delays related to a disability or mental illness
  • An unexpected hospital stay
  • The death of a partner or close family member
  • Fire, flood or theft
  • Computer or software failure
  • Issues with HMRC’s online services
  • Postal delays that you could not have predicted
  • You were unaware or misunderstood your obligation
  • Your authorised agent did not send your tax return.

How do I appeal a tax penalty from HMRC?

You can appeal online but only after you have filed your tax return (or informed HMRC that you didn’t need to file).

You’ll need:

  • the date the penalty was issued
  • the date you filed your Self Assessment tax return
  • details of your reasonable excuse for late filing

You can appeal online through a Government Gateway account or by post using form SA370 (or a letter). Each appeal is dealt with on a case by case basis.

I submitted my tax return to HMRC on time but made an error - what can I do?

You can resubmit your tax return before the next deadline but you must inform HMRC of the change. You may be penalised if found to have submitted incorrect information whether it was done deliberately or through accidental carelessness.

How can I be more prepared for next years tax deadline?

Most of us only start thinking about taxes when it's time to file. Because the UK tax year ends in April and starts in January, waiting until tax season means its too late to do anything about it. Recap makes it easy to track your cryptoassets and calculate your taxes and our new dashboard allows UK investors to proactively manage their crypto assets and tax affairs in unison. 2023-01-DASHBOARD-LAUNCH-BLOG-HEADER As well as helping you to declare for the filing tax year you can also view the active tax year. This understanding of your current gain and tax liability allows you to make the most of your allowances and optimise your taxes before year end. Log in now to maaximise your tax savings before the 2022/23 tax year comes to a close. Don't miss out on the opportunity to utilize the £12,300 capital gains allowance before it drastically decreases for the 2023/24 tax year.