--- title: "Registering for Self Assessment UK: A Guide for the 2026/27 Tax Year" description: For many individuals and businesses, registering for Self Assessment is the first formal step into the UK tax system beyond standard PAYE. It is a legal requirement for anyone with income that is not taxed at source. Also, failing to… url: "https://www.accountingfirms.co.uk/knowledge-bank/registering-for-self-assessment-uk/" updated: "2026-08-11" category: Getting Started --- # Registering for Self Assessment UK: A Guide for the 2026/27 Tax Year For many individuals and businesses, registering for Self Assessment is the first formal step into the UK tax system beyond standard PAYE. It is a legal requirement for anyone with income that is not taxed at source. Also, failing to register at the correct time can lead to penalties, so understanding the process is crucial. This guide provides a comprehensive overview of who needs to undertake [Self Assessment](https://www.accountingfirms.co.uk/blog/time-to-pay-arrangements-practicalities/) registration, the key deadlines, and the practical steps involved as of 19 June 2026. #### ## **Who Needs to Register for Self Assessment?** Any person who has not received a [tax return](https://www.accountingfirms.co.uk/blog/common-bookkeeping-mistakes-to-avoid/) must notify HMRC if they have a new liability to tax. While not an exhaustive list, Self Assessment registration is typically required for individuals in the following situations: | Category | Common Examples | | --- | --- | | **Self-Employed** | You are a sole trader or a partner in a business partnership. | | **Landlords** | You receive income from renting out a property. | | **High Earners** | Your total income is more than £150,000 in the tax year, or you need to pay the High Income Child Benefit Charge. | | **Significant Untaxed Income** | You have untaxed income from savings, investments, or dividends, or other untaxed income that cannot be collected through your tax code. | | **Capital Gains** | You have sold or disposed of an asset and need to pay [Capital Gains Tax](https://www.accountingfirms.co.uk/blog/going-going-almost-gone-what-is-left-of-badr/). | | **Company Directors** | Directors with untaxed income (unless it is for a non-profit and you do not receive pay or benefits). | | **Claiming Expenses** | You are an employee who needs to claim expenses worth over £2,500. | #### ## **What Is the Critical Registration Deadline** The deadline for registering for Self Assessment is a fixed date that taxpayers must not miss. For income received in the 2025/26 tax year (6 April 2025 to 5 April 2026), you must register by **5 October 2026**. This [deadline](https://www.accountingfirms.co.uk/blog/all-change-furnished-holiday-lettings/) is crucial because it relates to the requirement to notify chargeability to Income Tax or Capital Gains Tax for the first time. Moreover, the 5 October deadline ensures that HMRC has time to issue a tax return and a Unique Taxpayer Reference (UTR) before the filing period begins in earnest. #### ## **What Is the Step-by-Step Process of Registering for Self Assessment** Registering for Self Assessment is typically done online, and the process varies slightly depending on your circumstances. ### **Step 1: Gather Your Information** Before you begin, ensure you have the following details to hand: - National Insurance number - Full name, date of birth, and contact details - Business name and address (if self-employed) - The date your self-employment or other untaxed income started ### **Step 2: Register Online via Government Gateway** 1. **Create a Government Gateway Account:** If you do not already have one, you will need to create a Government Gateway user ID and password. This account will be your portal for all Self Assessment services. 2. **Complete the Registration Form:** Navigate to the "Register for Self Assessment" service on GOV.UK. You will be asked questions about why you need to register. - If you are registering as a **sole trader**, the system will guide you through the process for both income tax and Class 2 and [Class 4 National Insurance contributions](https://www.accountingfirms.co.uk/blog/in-with-the-new-basis-period-rules/). - If you are registering for **other reasons** (e.g., property income), you will complete a different online form (the equivalent of a paper form SA1). 3. **Submit Your Application:** Once you have filled in all the required information, submit your registration. ### **Step 3: What Happens Next?** After successfully registering for Self Assessment, HMRC will send you two important items by post: 1. **Unique Taxpayer Reference (UTR):** You will receive a letter containing your 10-digit UTR. So, this number is your permanent identifier for Self Assessment and is required for filing your tax return. Keep it safe. 2. **Activation Code:** Shortly after, you will receive a separate letter with an activation code to enrol for the Self Assessment online service. You must use this code to activate your account before you can file online. #### ## **After Registering: Your Ongoing Obligations** Once your Self Assessment registration is complete, you take on new legal responsibilities. - **Keep Records:** You must keep complete and accurate records of your business income and expenses to enable you to complete a correct tax return. - **File Your Tax Return:** You must file a tax return each year by the deadline (typically 31 January online for the preceding tax year). - **Pay Your Tax:** Yes, you must pay any tax owed by the deadline, which includes a balancing payment and potentially two 'payments on account'. ### **Making Tax Digital for Income Tax (MTD)** Individuals required to use MTD for [Income Tax](https://www.accountingfirms.co.uk/blog/mtd-for-income-tax-what-small-businesses-need-to-know/) will also need to be registered for Self Assessment. Under MTD, you will use compatible software to keep digital records and send quarterly updates of your income and expenses to HMRC, followed by a final declaration.     *For detailed guidance on specific registration scenarios, it is advisable to consult HMRC’s Self Assessment Manual (SAM) and the GOV.UK guidance on registering for and filing Self Assessment returns.* ## ## References 1. [VAT guide (VAT Notice 700) at 132](https://www.gov.uk/guidance/vat-guide-notice-700#:~:text=(https%3A%2F%2Fwww,that%20you%20were%20liable%20to&text=(https%3A%2F%2Fwww,to%20notify%20HMRC&text=Flat%20Rate%20Scheme,that%20you%20were%20liable%20to&text=Flat%20Rate%20Scheme,to%20notify%20HMRC) 2. [Enquiry Manual - EM0050 - Introduction: Self Assessment Tax System: Outline at 1](https://www.gov.uk/hmrc-internal-manuals/enquiry-manual/em0050#:~:text=Enquiry%20Manual%20EM0050%20%2D%20Introduction,the%20year%20of%20assessment%20A&text=Enquiry%20Manual%20EM0050%20%2D%20Introduction,31%20July%20after&text=Self%20Assessment%20Tax,the%20year%20of%20assessment%20A&text=Self%20Assessment%20Tax,31%20July%20after) 3. [Employment Income Manual - EIM71410 - Assessments, appeals and other procedures: self assessments at 1](https://www.gov.uk/hmrc-internal-manuals/employment-income-manual/eim71410#:~:text=Employment%20Income%20Manual%20EIM71410%20%2D,notice%20to%20complete%20a%20tax&text=Employment%20Income%20Manual%20EIM71410%20%2D,been%20given%20a&text=Assessments%2C%20appeals%20and,notice%20to%20complete%20a%20tax&text=Assessments%2C%20appeals%20and,been%20given%20a) 4. [Self Assessment Manual - SAM101042 - Records: maintain taxpayer record: criteria for auto removal of cases from SA using CY-1 return at 1](https://www.gov.uk/hmrc-internal-manuals/self-assessment-manual/sam101042#:~:text=Relief)%20*%20Box%205%20on,pension%20schemes%20and%20overseas%20pension&text=Relief)%20*%20Box%205%20on,(Paying%20into%20registered&text=page%20Ai%202,pension%20schemes%20and%20overseas%20pension&text=page%20Ai%202,(Paying%20into%20registered)