Understanding Self Assessment and your tax return
Tools and videos to help you complete and file your Self Assessment tax return on time
Self Assessment is a system HM Revenue & Customs (HMRC) uses to collect Income Tax. Income Tax is usually deducted automatically from wages, pensions and savings. However, people and businesses with other income must report it in a Self Assessment tax return.
Do I need to file a Self Assessment tax return?
You can find out who must send a tax return and check if you need to fill in a Self Assessment return.
Self Assessment deadline
The deadline to submit your Self Assessment tax return and pay the tax you owe is midnight on 31 January 2021 (you can submit your return up to 28 February 2021 without getting a late filing penalty).
This guide will help you understand Self Assessment including how to register for Self Assessment with HMRC, how to file your first Self Assessment tax return and key deadlines for Self Assessment.
Register for Self Assessment (video)
How to register with HM Revenue & Customs for Self Assessment
You will need to register for Self Assessment with HM Revenue & Customs (HMRC) if you have to send a tax return but didn't send one the previous year.
Self Assessment registration process time
You should note that it can take up to 20 working days to complete the registration process. You should take this into consideration to give yourself plenty of time to complete your Self Assessment return ahead of the 31 January deadline.
Watch this short HMRC video explaining how to register your new business online with HMRC so that you can complete a Self Assessment return.
Self Assessment tax return deadlines
Important deadline dates for your Self Assessment tax returns
You must send your Self Assessment tax return and pay any tax you owe to HM Revenue & Customs (HMRC) on time. There are a number of deadlines for Self Assessment that you must keep in mind.
The last tax year started on 6 April 2019 and ended on 5 April 2020.
Self Assessment deadlines
- Register for Self Assessment by 5 October 2020
- Paper tax returns midnight 31 October 2020
- Online tax returns midnight 31 January 2021 (you can submit your return up to 28 February 2021 without getting a late filing penalty - see Self Assessment deadline reminder)
- Pay the tax you owe midnight 31 January 2021 (if you pay your tax or set up a payment plan by 1 April 2021 you will not be charged the initial 5% late payment penalty - more help for Self Assessment taxpayers)
If you fail to meet the deadline you may have to pay a penalty.
When the deadline is different
Submit your online return by 30 December if you want HMRC to automatically collect tax you owe from your wages and pension. You must be eligible.
HMRC must receive a paper tax return by 31 January if you're a trustee of a registered pension scheme or a non-resident company. You can't send a return online.
Complete your Self Assessment tax return (video)
How to complete and submit your Self Assessment tax return online
Watch this short HM Revenue & Customs (HMRC) video with simple guidance on how to fill in and submit your Self Assessment tax return. This video is particularly useful if you are completing your first Self Assessment tax return.
View your Self Assessment calculation (video)
How to view your online tax calculation for Self Assessment
When you use HM Revenue & Customs (HMRC) online tax return it automatically works out how much you have to pay by providing you with a result of your calculation.
View this short HMRC video explaining how to view your Self Assessment calculation:
Pay your Self Assessment tax bill (video)
How to pay your Self Assessment tax bill
Your tax bill refers to your bill for income tax and any Class 4 National Insurance contributions you may owe to HM Revenue & Customs (HMRC).
View this short HMRC video explaining how you pay your Self Assessment tax bill including various payment methods and payment deadline dates:
Self Assessment penalties (video)
Penalties that can be applied if you fail to submit and pay your Self Assessment on time
You may face paying a penalty if you don't submit your Self Assessment tax return on time. You may also face a penalty if you don't pay the tax you owe to HM Revenue & Customs (HMRC) by the appropriate deadline.
View this short HMRC video explaining the penalties that can be applied in the Self Assessment system:
Budget for your Self Assessment tax bill (video)
How to budget and prepare for your Self Assessment tax bill
View this short HM Revenue & Customs (HMRC) video explaining how you can budget and prepare ahead for your Self Assessment tax bill including how to use the Ready Reckoner tool for the self-employed and information on the budget payment plan:
Expenses if you’re self-employed (video)
Expenses you can claim if you’re self-employed and listing these in your tax return
If you are self-employed you may need to understand pre-trading expenses, day to day revenue expenses, capital allowances and using flat rates or simplified expenses. Access the HM Revenue & Customs (HMRC) self-employed business expenses e-learning tool.
You can also view this short HM Revenue & Customs (HMRC) video explaining expenses you can claim if you're self-employed and how to account for these in your Self Assessment tax return:
If you cannot pay your tax bill on time
You must arrange to pay your tax bill with HM Revenue and Customs (HMRC) if you either miss a payment or know you cannot pay on time
You must arrange to pay your tax bill with HM Revenue and Customs (HMRC) if you either:
- miss a payment
- know you cannot pay on time
If you pay a tax bill late you must pay interest on the amount you owe until it’s paid off. You can avoid penalties by arranging a payment plan with HMRC before the tax is due.
If you owe Self Assessment tax and your bill is less than £30,000 you may be able to pay in monthly instalments.
For any other bills or problems paying, you must contact HMRC to discuss your options. How you contact HMRC depends on what you need to pay.
If you cannot pay because of coronavirus (COVID-19)
You may be able to pay your Self Assessment tax in monthly instalments. This includes any delayed (deferred) ‘payments on account’ that were due in July 2020, if you did not pay them at the time.
Contact the HMRC coronavirus (COVID-19) helpline if you cannot pay any other tax bills because of coronavirus.
If you’re self-employed
If your business has been affected by coronavirus (COVID-19), you may be able to claim a grant through the Self-Employment Income Support Scheme.
If you cannot pay your Self Assessment tax bill
You can set up a payment plan online to spread the cost of your latest Self Assessment bill if:
- you owe £30,000 or less
- you do not have any other payment plans or debts with HMRC
- your tax returns are up to date
- it’s less than 60 days after the payment deadline
You do not need to contact HMRC if you set up a payment plan.
Call the Self Assessment helpline if you’re not eligible for a payment plan or cannot use the online service.
Telephone: 0300 200 3822
Monday to Friday, 8am to 6pm (closed on bank holidays)
Find out about call charges
If you cannot pay other taxes
You might be able to set up a Time to Pay Arrangement with HMRC if you’re unable to pay any other taxes in full. This lets you spread the cost of your tax bill by paying what you owe in instalments.
How you do this depends on whether you’ve received a payment demand.
If you’ve received a payment demand, like a tax bill or a letter threatening you with legal action, call the HMRC office that sent you the letter.
If you’ve not received a bill or letter, call the Payment Support Service (PSS).
Telephone: 0300 200 3835
Monday to Friday, 8am to 6pm (closed on bank holidays)
Find out about call charges
Nominated partners in business partnerships can negotiate a Time to Pay Arrangement with HMRC on behalf of the partnership or individual partners.
Before you contact HMRC
You’ll need to know:
- your reference number (for example, your 10-digit Unique Taxpayer Reference or VAT reference number)
- the amount of the tax bill you’re finding it difficult to pay and the reasons why
- what you’ve done to try to get the money to pay the bill
- how much you can pay immediately and how long you may need to pay the rest
- your bank account details
What happens when you contact HMRC
HM Revenue and Customs (HMRC) will ask you about:
- your income and expenditure
- your assets, like savings and investments
- what you’re doing to get your tax payments back in order
HMRC will decide whether you should be able to pay immediately. If you cannot, they’ll decide whether you’ll be able to get your payments back on track with more time.
You’ll be asked more in-depth questions if you’ve been given more time to pay before. In more complex cases HMRC may ask for evidence before they make a decision.
What happens next
You’ll have to pay immediately if HMRC think you can when you call. You can pay by Direct Debit, corporate credit card or debit card over the phone.
You’ll be charged a fee if you pay by credit card. The fee is not refundable.
If you cannot pay all your tax bill, you may be able to:
- pay your bill in instalments by Direct Debit
- get more time to pay
When you might get more time to pay
HMRC may offer you extra time to pay if they think you genuinely cannot pay in full now but will be able to pay in the future.
You can set up a plan to pay in instalments by Direct Debit on dates they agree with you.
Tell HMRC as soon as possible if your circumstances change and you can pay your tax bill faster.
You’ll have to pay interest on the amount you pay late.
You must keep these payments up to date and pay your other tax. If you do not, HMRC will normally cancel the arrangement and take legal action against you straight away.
When you will not get more time to pay
If HMRC do not think you can get your payments on track with more time, they will not make an arrangement with you - they’ll expect you to pay your tax bill straight away.
If you do not, HMRC will start ‘enforcement action’ to get the money from you.
Help and advice
You can also contact HMRC.
Making a complaint
You cannot appeal against HMRC’s decision, but you can make a complaint if you’re unhappy about how you were treated.