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5 Min. Read

What Is the Self-Assessment Tax Return Deadline?

What Is the Self-Assessment Tax Return Deadline?

For the majority of self-employed taxpayers, the deadline for filing your self-assessment tax return and paying your income tax bill is the same. There are a few exceptions, which relate to less common circumstances, like paper filing and paying through PAYE.

FreshBooks has it all laid out for you. So you can get these dates in your diary and work backwards to plan what you need to do. And – importantly – avoid any of those late filing penalties.

Here’s What We’ll Cover:

Critical Dates

When Is the Deadline Different?

What is ‘Payment On Account’?

What Is a 'Time to Pay' Arrangement?

What Happens If I Miss the Deadline?

But What if I’ve Got a Good Reason for Missing the Deadline?

Critical Dates

Let’s focus on the 2020-21 tax year. This started on April 6th 2020 and finished on 5th April 2021.

If you need to register for self-assessment for the first time, this needs to be done by 5th October 2021.

  • Paper tax returns: Self-assessment deadline to file a paper tax return - midnight 31st October 2021
  • Online tax returns: Self-assessment deadline to file an online tax return – midnight 31st January 2022
  • Paying your 2020-21 tax bill: Self-assessment deadline to pay - midnight 31st January 2022

When Is the Deadline Different?

This 31 January deadline can be different if you're in particular circumstances.

Paying Through Your Tax Code

This deadline is usually for people who are both employed and self-employed simultaneously.

HMRC let you pay your self-assessment income tax bill through your PAYE tax code, if you meet their criteria:

  • Your self-assessment tax bill is under £3,000
  • You pay tax through PAYE
  • You submit your online self-assessment tax return by 30th December

Partnerships Where a Company Is a Partner

If your partnership has a company as a partner and your accounting date is from 1st February and 5th April, you have a different tax return filing deadline.

  • Paper returns - 9 months from your accounting date
  • Online returns – 12 months from your accounting date

What is ‘Payment On Account’?

Payments on account are “advance payments towards your tax bill.” Basically, this means your tax bill is split in half, with 2 separate deadlines 6 months apart:

  • Deadline for first payment on account: 31st January
  • Deadline for second payment on account: 31st July

You don’t have to make payments on account if:

  • You’re paying your self-assessment tax bill through your PAYE tax code and you’ve already paid 80% of the total. This also applies if your bank has deducted interest from your savings.
  • Your previous self-assessment tax bill was under £1,000.

Your deadline for filing a digital tax return remains the same.

None of these self-assessment deadlines are negotiable. You need to work out when your self-assessment tax returns and payments are due and sort out your paperwork as soon as possible after the tax year ends.

What Is a 'Time to Pay' Arrangement?

If your self-assessment tax bill is under £30,000, you can set up a time to pay arrangement with HMRC online. It's designed as a one-off payment plan to support businesses through difficult times. If you don't keep up with the payments, HMRC can ask for the total of your tax bill to be settled in one go.

With a time to pay arrangement, you can pay your tax bill in 12 monthly installments. You still pay interest, if you're late, but it stops any fines building up. You must have a clean record with HMRC, no outstanding tax debts and no other payment plans set up with them. You must also have filed your 2019 to 2020 tax return. The online service can be used to establish your payment plan within 60 days of the payment deadline.

If you're over this time period, or owe more than £30,000, you need to get in touch with HMRC to discuss your options on the Self Assessment Payment Helpline number 0300 200 3822.

What Happens If I Miss the Deadline?

HMRC imposes fines if you miss the self-assessment tax return filing deadline and if you’re late paying your tax bill. They are cumulative – the longer past the deadline you go, the more filing penalties will be.

Fines for missing the self-assessment tax return filing deadline

  • 1 day late: £100
  • Up to 3 months late: £10 per day, up to 90 days + £100
  • Up to 6 months late: £300 of 5% of your tax bill (the higher figure) + previous penalties
  • 12 months late: £300 or 5% of your tax bill (the higher figure) + previous penalties

You can be fined 100% of the tax due, in the most severe cases.

Fines for paying your tax bill late

  • 30 days late: 5% of tax owed
  • 6 months late: another 5% of tax owed
  • 12 months late: another 5% of tax owed

You also pay interest on the total of any late payments, at a current rate of 2.6%.

By the time you add late filing penalties, late payment fines and the interest charges, you can end up owing a substantial amount of money.

But What if I’ve Got a Good Reason for Missing the Deadline?

HMRC has a list of ‘reasonable excuses’ and it considers all appeals on a case-by-case basis. If they accept that you have a reasonable excuse for missing the deadline, then late fees are cancelled.

These excuses are what you’d expect, emergencies or circumstances outside your control. What HMRC calls “normally something unexpected or outside your control that stopped you meeting a tax obligation”.

These include, but aren’t limited to:

  • Death of a close relative or partner near the deadline
  • Your suffered a serious life threatening illness, or had to stay in hospital
  • ‘Acts of God’ – like fire or flood
  • HMRC online services ‘issues’

These are very specific reasons, which aren’t considered to be flexible.

COVID-19 Concession

HMRC suspended the automatic £100 late filing penalty for the 2019-20 tax return. In order to help people struggling because of the impact of the health pandemic, this deadline was extended from 31st January to 28th February 2021. The deadline to pay your tax bill stayed the same.


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