Deadlines
HMRC must receive your tax return and any money you owe by the following deadlines –
- Paper tax returns – Midnight 31 October
- Online tax returns – Midnight 31 January
- Pay the tax you owe – Midnight 31 January
If you want HMRC to automatically collect tax you owe from your wages and pension, you must be eligible and submit your online return by 30 December.
Penalties
You’ll get a penalty if you need to send a tax return and you miss the deadline for submitting it or paying your bill.
Changes to your return
You can make a change to your tax return after you’ve filed it, for example because you made a mistake. You’ll need to make your changes by:
- 31 January 2022 for the 2019 to 2020 tax year
- 31 January 2023 for the 2020 to 2021 tax year
You’ll see your amended bill straight away if you updated your tax return online. Within 3 days, your statement will also show:
- the difference from the old one, so you can see whether you owe more or less tax
- any interest
If you miss the deadline or if you need to make a change to your return for any other tax year, you’ll need to write to HMRC.
Appeal against a penalty
If HMRC sends you a penalty letter by post, use the appeal form that comes with it or follow the instructions on the letter.
You can get your penalty cancelled if you did not send a tax return because you no longer needed to. Tell HMRC online you do not need to be self-assessed or call the helpline.
Otherwise, to appeal 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
Reasonable excuses
You can appeal against some penalties if you have a reasonable excuse, for example for your return or payment being late.
A reasonable excuse is something that stopped you meeting a tax obligation that you took reasonable care to meet, for example:
- your partner or another close relative died shortly before the tax return or payment deadline
- you had an unexpected stay in hospital that prevented you from dealing with your tax affairs
- you had a serious or life-threatening illness
- your computer or software failed just before or while you were preparing your online return
- service issues with HM Revenue and Customs (HMRC) online services
- a fire, flood or theft prevented you from completing your tax return
- postal delays that you could not have predicted
- delays related to a disability you have
You must send your return or payment as soon as possible after your reasonable excuse is resolved.
HMRC may consider COVID-19 as a reasonable excuse for missing some tax obligations (such as payments or filing dates).
Explain how you were affected by COVID-19 in your appeal. You must still make the return or payment as soon as you can.
The following will not be accepted as a reasonable excuse:
- you relied on someone else to send your return and they did not
- your cheque bounced or payment failed because you did not have enough money
- you found the HMRC online system too difficult to use
- you did not get a reminder from HMRC
- you made a mistake on your tax return
Please also read FKGB blog on payment on account: Payments on Accounts – Self Assessment | FKGB Accounting
