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Getting ready for Self Assessment — a 10 point step-by-step guide

Updated 12 May 2026

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This publication is available at https://www.gov.uk/government/publications/submit-your-self-assessment-tax-return-early/top-tips-for-filing-your-tax-return

1. Check if you need to do a tax return

Use HMRC’s online checker to see if you need to submit a tax return. It’s quick and easy to use. You simply answer a few questions (it’s anonymous) and it provides a tailored response on whether you need to complete a tax return.

You will normally need to submit a tax return if any of the following apply:

  • you were self-employed as a ‘sole trader’ and earned more than £1,000 (before taking off anything you can claim tax relief on)
  • you were a partner in a business partnership
  • you had to pay Capital Gains Tax when you sold or ‘disposed of’ something that increased in value
  • you had to pay the High Income Child Benefit Charge and do not pay it through PAYE

You may also need to send a tax return if you have any untaxed income, such as:

  • money from renting out a property
  • tips and commission
  • income from savings, investments and dividends
  • foreign income

If you used the checker and you no longer need to do a tax return, tell HMRC as soon as possible — preferably through the online service as it’s quicker. If you don’t let HMRC know, they’ll continue sending you reminders. If you don’t submit a tax return, you may get a penalty — even if you don’t owe any tax.

Don’t assume somebody else will tell HMRC or that they already know — make sure you tell them to make it official.

2. Registering or reactivating Self Assessment

If you need to complete a tax return, the quickest and easiest way to tell us is by registering for Self Assessment on GOV.UK.

Once registered, you’ll receive a letter, known as a Notice to File and your Unique Taxpayer Reference (UTR). You’ll need your UTR to submit your tax return.

If you’ve previously been in Self Assessment and did not submit a tax return last year, you do not need to register again. Instead, you’ll need to reactivate your Self Assessment account on GOV.UK before submitting your tax return.

If it’s the first time you need to send a tax return, you should register for Self Assessment (or reactivate your account) by 5 October following the end of the tax year you need to report for.

3. Get ready

Gather all the information you need and make a start your tax return. You don’t have to complete it in one go — you can save your progress and come back to it later. Many people set themselves reminders and set aside small chunks of time until it’s done.

If you know a particular month is going to be busy for your business, or you are planning to take time off, factor this in so you don’t leave it until the last minute.

You will need:

  • your National Insurance number
  • details of untaxed income — for example bank statements, records of rental income, receipts, invoices and any other relevant information
  • details from employment income where tax was deducted at source, including your P60, P45 (if you changed jobs) or P11D (for benefits and expenses)
  • records of your self-employed income and allowable expenses
  • pension statements
  • records of capital gains from selling or disposing of assets
  • records of overseas income
  • details of eligible tax reliefs, such as pension contributions or Gift Aid donations

Some of the personal information you need to complete your tax return is available in your HMRC online account or in the HMRC app.

Remember to keep records in case HMRC wants to check the information later.

4.  Gather HMRC information

Check that you have your:

Unique Taxpayer Reference (UTR)

You’ll need your Unique Taxpayer Reference (UTR) to complete your tax return. This allows HMRC to identify you.

You can find your UTR:

  • on previous tax returns
  • on other Self Assessment letters or documents such as statements or payment reminders
  • in your HMRC online services account or the HMRC app

Access to HMRC online services

You’ll need access to HMRC online services to complete and submit your tax return. Check that you have your user ID and password.

If you’ve lost these details, you can get help signing into your account.

If you do not already have an HMRC online account, you’ll need to set one up to submit your online tax return and to view all your tax information.

5. Complete your online tax return by the deadline

You’ll need to submit your tax return by 31 January 2027, but it’s better to file early — find out why.

It’s easier than it looks, you don’t need to be an expert. Take it one step at a time, saving it as you go. Come back to it at any time to add information or correct any mistakes before submitting it.

Check your information before you submit your tax return, so you’re confident it’s correct and make sure you press the submit button when the progress bar shows 100% complete.

You can quickly and easily change your online tax return after you’ve submitted it. If you change it, it might mean you may have to pay more tax or it might mean you’re able to claim a refund.

Although you do not need to pay until 31 January 2027, some people who are employed and pay tax through PAYE may be able to pay what they owe through their PAYE tax code. To do this, you must submit your tax return by 30 December 2026.

6. How and when to pay your bill

If you submit your tax return early, you won’t need to pay your tax bill until 31 January 2027. Submitting early means you’ll know how much you owe and can plan and budget in advance.

Find out how to pay your Self Assessment tax bill.

Payments on account

Some people are required to make payments on account. These are advance payments towards your tax bill. For the 2025 to 2026 tax year, payments on account are usually:

  • 31 January 2026 — a first payment on account
  • 31 July 2026 — second payment on account

If you expect your tax bill 2025 to 2026 to be lower than the previous tax year, you can make a claim to reduce your payment on account. It is important to remember that if you reduce your payments on account too much, you may be charged interest on the difference.

Understand your Self Assessment tax bill - payments on account.

7. Budgeting to pay your tax bill

You can use a Budget Payment plan to make regular weekly or monthly payments towards your next tax bill. You must be up to date with your previous Self Assessment payments and you can decide how much to pay each week or month.

Set up your plan using your HMRC online account. Go to the Direct Debit section and choose the ‘set up a Budget Payment plan’ option when filling in the Direct Debit form. If the amount in your Budget Payment plan does not cover your next bill in full, you will need to pay the difference by the payment deadline. If you are in credit, you can ask for a refund.

Find out more about budget payment plans.

8. Refunds

If you have overpaid tax in the 2025 to 2026 tax year, it will show it on your Self Assessment calculation when your tax return is processed. You can request a refund, but in some cases HMRC may automatically offset your refund against tax that’s due — for example, for a payment on account due in the next 45 days. Your online account may show the status as ‘pending’ while it’s being approved. Submitting your tax return online usually speeds things up.

9. If your details change

It’s important to let us know of any changes to your details or circumstances, such as:

  • a new address or name
  • new contact details

Don’t assume someone else will update us — you can do this yourself on GOV.UK.

10. Help and support

HMRC wants to help you get your tax right. Lots of information and support is available which includes:

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