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How to File Self Assessment Tax Return

A Self-Assessment Tax Return is a document that individuals in the UK must complete annually to report their income, gains, and claim any tax reliefs or allowances they are entitled to. This process is primarily used by self-employed individuals, sole traders, landlords, and high earners to declare their earnings and calculate the amount of tax they owe to HM Revenue and Customs (HMRC).

The tax return requires individuals to provide detailed information about their income sources, allowable expenses, and deductions. It serves as a means for taxpayers to accurately report their financial affairs to ensure they are paying the correct amount of tax based on their earnings. Filing a Self-Assessment Tax Return is a legal obligation for those who fall under HMRC's criteria and plays a significant role in the UK's tax system.

When Do I Need to Fill Out a Self Assessment Tax Return?

When Do I Need to Fill Out a Self Assessment Tax Return?

You may need to file a Self-Assessment Tax Return if certain criteria apply to your financial situation. Here are some scenarios that typically necessitate filing:

  • Your self-employment income exceeded £1,000 before claiming tax relief.

  • Income from property rental was over £2,500 (or between £1,000 and £2,500, requiring HMRC contact).

  • Untaxed income, like tips or commission, exceeded £2,500.

  • Savings or investment income before tax was £10,000 or more.

  • Capital Gains Tax is payable from selling shares or a second home.

  • You're a company director (except for non-profit organizations).

  • Your or your partner's income exceeded £50,000 while claiming Child Benefit.

  • Foreign income necessitating UK tax payment or residency abroad with UK income.

  • Taxable income surpassed £100,000.

  • Earnings over £50,270 in 2023/24 with pension contributions might require an assessment to claim additional tax relief.

  • Trustee of a trust or registered pension scheme.

  • Sole reliance on the State Pension, exceeding the personal allowance.

  • Received a P800 from HMRC indicating insufficient tax payment last year.

Moreover, if you aim to make voluntary Class 2 National Insurance contributions, filing a Self-Assessment tax return can help qualify for benefits like the State Pension. Note that from April 2024, self-employed individuals won't need to pay Class 2 National Insurance contributions when completing taxes.

Generally, if you're an employee paying tax through the PAYE system and earned under £100,000, filing a Self-Assessment tax return may not be necessary.

You can find out if you need to fill in a Self Assessment tax return at GOV.UK

What Documents Do I Need to File a Self Assessment Return?

When filing a Self-Assessment tax return, maintaining specific documents is crucial to presenting a comprehensive overview of your financial status to HMRC. Here are key documents to retain:

  1. Form P45: If employment ceased within the tax year, this document is essential.

  2. Form P60: Provides details about the tax paid during the year.

  3. Form P11D: Necessary if you received "benefits in kind" like a company car.

  4. Records of Taxed Award Schemes or Redundancy Payments: Important for accurate reporting.

  5. Additional Income Records: Include untaxed tips, incentive payments, or non-cash benefits like meal vouchers.

It's important to note that filing a Self-Assessment tax return isn't exclusive to the self-employed. Individuals claiming tax rebates for expenses exceeding £2,500 also need to utilize this system for accurate reporting and potential rebates. By retaining and organizing these documents, taxpayers ensure a smooth and accurate filing process while meeting HMRC's requirements.

You can read here : sheets at GOV.UK

How to Register for a Self Assessment Tax Return

For individuals in the UK looking to register for a Self Assessment tax return, here's a step-by-step guide:

1. First-Time Registration

If you've never submitted a return before, register for Self Assessment using the appropriate method based on your employment status. Self-employed individuals or those needing to declare income should register differently than those in partnerships.

2. Receiving Unique Taxpayer Reference (UTR)

Once registered, HMRC will issue your Unique Taxpayer Reference (UTR).

3. Setting Up Government Gateway Account

To file online, create a Government Gateway account following the instructions provided with your UTR letter.

4. Activation Code

Upon setting up the account, you'll receive an activation code via post. Complete the setup of your Gateway account using this code.

5. For Previous Filers

If you've filed Self-Assessment returns before, use your old UTR to register and set up the account.

6. Check Account Access

Ensure smooth access to your Gateway account before attempting to submit your Self Assessment, saving time in case of any login issues.

More Details read this Blog : Register as Self Employed in the UK

Information Required for Filing a Self-Assessment Tax Return

When preparing to fill out a self-assessment tax return in the UK, gathering specific information beforehand simplifies the process. Here's what you'll need:

  • Ensure you have your ten-digit UTR, a unique identifier issued by HMRC.

  • Your National Insurance number is crucial for identification purposes.

  • Collate information about untaxed income from various sources, such as self-employment, dividends, and share interest.

  • Maintain accurate records of any expenses linked to self-employment for potential deductions.

  • Note down contributions eligible for tax relief, whether to charity or pension schemes.

  • Gather records like P60 or other documents illustrating income already subjected to tax.

Additionally, familiarizing yourself with relevant HMRC help sheets, especially those concerning supplementary pages relevant to your circumstances, is advisable. This comprehensive preparation ensures a smoother and accurate filing process for your Self-Assessment tax return.

Penalties Under Self Assessment

Here's a breakdown of the penalties John faced for his late filing of the 2021-22 Self-Assessment tax return:

Trigger Date

Penalty Incurred

Missed filing deadline: 31 Jan 2023


Unfiled after 3 months: deadline 30 April 2023

£10 per day for 90 days

Unfiled after 6 months: deadline 31 July 2023

£300* reduced to £100

Unfiled after 12 months: deadline 31 Jan 2024

£300* reduced to £nil


  • If you missed the initial filing deadline on 31st January 2023, incurring a fixed penalty of £100.

  • After three months, starting from the deadline, you faced a daily penalty of £10 for 90 days.

  • The penalty increased after six months to £300, but HMRC reduced it to £100 as if you filed the return after that duration but within 12 months.

  • If you submitted the return after 12 months but before the 31st January 2024 deadline, the £300 penalty was waived off entirely by HMRC.

Paying Your Self Assessment Tax Bill

Here are key points regarding paying your Self Assessment tax bill, based on the information from the provided link:

  1. Payment Deadlines: Ensure timely payment by the due dates specified by HM Revenue and Customs (HMRC) to avoid penalties and interest charges.

  2. Payment Options: Various methods are available to pay the tax bill, including:

    1. Online bank transfer

    2. Direct debit

    3. Debit or credit card

    4. Through your bank

    5. Cheque

  3. Using the Government Gateway: Pay securely online using the Government Gateway service via the HMRC website.

  4. Set Up a Payment Plan: If unable to pay in full by the deadline, individuals can set up a payment plan with HMRC, but interest might apply.

  5. Payment Reference: Ensure the correct payment reference is used to link the payment to your Self Assessment account.

  6. Confirmation of Payment: After payment, HMRC sends a confirmation via email or letter, confirming the amount paid and the date.

  7. Review Payment Methods: Regularly review payment methods to ensure compliance with HMRC requirements and avoid potential issues in the future.

For detailed information and instructions on how to make payments, refer to the official HMRC page.

What to Do If You Can't Afford to Pay Your Tax Bill

If you find yourself unable to afford your tax bill, it's crucial to take prompt action. Contact HMRC at the Business Payment Support Service immediately. Follow these steps:

a) Immediate Contact

Reach out to HMRC through the Business Payment Support Service at 0300 200 3825. This service caters to all individuals, not just businesses.

b) HMRC will assess your situation based on:

  • Evaluation of the owed amount.

  • Review of your income, expenditure, assets, savings, and investments.

c) Potential Solutions

  • Depending on the assessment, HMRC may grant you additional time to settle the bill.

  • You might be offered the chance to pay in instalments to ease the payment burden.

d) Importance of Prompt Action

  • Priority Debt: Tax is considered a priority debt. If unable to pay or facing difficulties, contact the Business Payment Support Service immediately at 0300 200 3835.

  • Consequences of Non-Payment: Failure to address the issue may lead to interest and penalty charges, enforcement actions such as direct collections from earnings, bank accounts, pensions, or even legal actions like court proceedings, bankruptcy, or business closure.

To avoid severe consequences, proactively engaging with HMRC and seeking their assistance is essential if you're unable to afford your tax bill.

Optimal Accounting Services in UK for Self-Assessment Tax Returns

FCCA Accounts, a reputable London-based company specializing in Tax Returns. Our expert team ensures seamless handling of your financial matters, delivering top-notch services including VAT Returns in London, CIS Returns, and Payroll Services in London.

At FCCA Accounts, we understand the intricacies of Self-Assessment Tax Returns, offering tailored solutions to meet your specific needs. Our dedicated professionals are well-versed in navigating the complexities of tax regulations, providing meticulous attention to detail while ensuring compliance.

Experience peace of mind and exceptional service standards with FCCA Accounts, your trusted partner in managing Self-Assessment Tax Returns and various financial obligations within London.


Filing a Self Assessment Tax Return might seem complex, but with careful preparation and attention to detail, it becomes manageable. It's a critical process that ensures compliance and helps individuals understand and manage their tax responsibilities effectively.


Can I file my Self Assessment Tax Return after the deadline?

Filing after the deadline may incur penalties, but it's still advisable to submit the return even if late.

Are there any consequences for incorrect information on the tax return?

Providing incorrect information may lead to penalties or further inquiries from HMRC. Accuracy is crucial.

What happens if I miss claiming allowable deductions?

Missing deductions means potentially paying more tax than necessary. It's vital to review and claim all applicable deductions.

Can I rectify errors in my submitted tax return?

Yes, you can amend errors or provide additional information after submission within a certain timeframe.

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