Understanding Self Assessment and your tax return

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.

First-time Self Assessment registration

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.

HMRC also provides video guidance on how to register for Self Assessment if you are not self-employed.

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.

Self Assessment deadlines

There is usually a second payment deadline of 31 July if you make advance payments towards your bill, known as payments on account.

If you fail to meet the deadline, you may have to pay a penalty. You can appeal against a penalty if you have a reasonable excuse.

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.

Partnership returns if you have a company as a partner

If your partnership’s accounting date is between 1 February and 5 April and one of your partners is a limited company, the deadline for:

• online returns is 12 months from the accounting date
• paper returns is 9 months from the accounting date

2023 to 2024 tax year and earlier

The Self Assessment deadline for these tax years has passed. Send your tax return or payment as soon as possible - you’ll have to pay a penalty.

Watch this short HM Revenue & Customs 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.

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:

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:

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 and how you can appeal against a Self Assessment late filing penalty:

View this short HM Revenue & Customs 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:

If you are self-employed, you may need to understand pre-trading expenses, day-to-day revenue expenses, capital allowances, and the use of flat rates or simplified expenses.

You can view this short HM Revenue & Customs 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 Self Assessment tax bill in full, you may be able to set up a payment plan to pay it in instalments.

HM Revenue and Customs (HMRC) will check if a payment plan is affordable for you. If you cannot agree on a payment plan with them, they'll ask you to pay the amount you owe in full.

Setting up a payment plan

You may be able to set up a payment plan to pay your overdue tax bill in monthly instalments.

To set up a payment plan, you’ll need:

• the relevant reference number for the tax you cannot pay, such as your unique tax reference number - you can usually get this from any letters HMRC has sent you
• your UK bank account details - you must be authorised to set up a Direct Debit
• details of your income and spending, or your company’s income and spending, if you owe company tax

Set up a payment plan online

Use this service to check if you’re eligible for and to set up a payment plan online.

Start now

If you cannot set up a payment plan online

You’ll need to tell HMRC:

• if you can pay in full
• how much you can repay each month
• if there are other taxes you need to pay
• how much money you earn
• how much you usually spend each month
• what savings or investments you have

Contact HMRC to set up a payment plan.

If you have savings or assets, HMRC will expect you to use these to reduce your debt as much as possible.

If you’ve received independent debt advice, for example, from Citizens Advice, you may have a ‘Standard Financial Statement’. HMRC will accept this as evidence of what you earn and spend each month.

If your company is in tax debt

HMRC will ask you how you’ll pay your tax bill as quickly as you can. They will ask questions about your proposal to make sure it is realistic and affordable for you.

You must reduce your debt as much as possible before setting up a payment plan. You can do this by releasing assets like stock, vehicles and shares.

HMRC may ask company directors to:

• put personal funds into the business
• accept lending
• extend credit

How much will you pay?

The amount you’ll be asked to pay each month will be based on how much you have left after you pay any rent, food or utility bills and fixed outgoings you have, like subscriptions.

You’ll usually be asked to pay around half of what you have left over each month towards the tax you owe.

You can also agree to pay more if you want. Paying your debt quicker means you’ll pay less in total because you’ll pay less interest.

How long does your payment plan last?

There’s no time limit on how long a payment plan can last. It will depend on how much you owe and what you can afford to pay each month.

You should contact HMRC if anything changes that could affect your payment plan. You can make the payment plan longer or shorter.

If you miss a payment

HMRC will contact you to find out why. Where possible, they’ll try to rearrange or renegotiate the payment plan with you.

If you cannot pay another tax bill, contact HMRC. You may be able to include the new tax bill in your payment plan.

If you do not contact HMRC or refuse to pay

HMRC will always try to contact you if you miss a tax payment. This can include sending you letters, texts and visiting you at home or at work.

If you do not get in contact with HMRC or cannot agree on an instalment plan, then HMRC may:

• ask a debt collection agency to collect the money
• collect what you owe directly from your wages or any monthly pension payments you get
• take things you own and sell them (if you live in England, Wales or Northern Ireland)
• take money directly from your bank account or building society savings (if you live in England, Wales or Northern Ireland)
• take you to court
• make you bankrupt
• close down your company if the tax is a business tax

Any costs, like auction fees, are normally added to your debt. HMRC will tell you before taking any of these actions and will explain your rights, costs and options.

Read more about actions HMRC can take to recover tax.

Help and advice

Northern Ireland businesses can get free debt advice from Advice NI.

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.

You must tell HM Revenue and Customs (HMRC) if you’ve stopped trading as a sole trader or you’re ending or leaving a business partnership.

You’ll also need to send a final tax return.

Watch this short HMRC video explaining how to go online and stop Self Assessment if you're self-employed: