Common Mistakes to Avoid When Filing Your Self-Assessment Tax Return

Once the deadline for filing self-assessment tax returns approaches, many individuals begin to feel the pressure of ensuring they file their returns accurately and on time. Filing your tax return can be a daunting task, especially if you are not familiar with the process or requirements. In this article, we will discuss common mistakes to avoid when filing your self-assessment tax return.

What is Self-Assessment Tax Return?

A self-assessment tax return is a form that taxpayers in the UK need to fill out to report their income and capital gains to HM Revenue & Customs (HMRC). The tax return also calculates how much tax is due for the year. Taxpayers need to file their tax returns online or by paper, before the deadline.

Importance of Filing Self-Assessment Tax Return Accurately and on Time

Filing your self-assessment tax return accurately and on time is vital to avoid penalties and interest charges. The penalties increase the longer you wait to file your return. Additionally, filing your tax return accurately ensures that you pay the correct amount of tax and can claim all available deductions and credits. Read this article to get a brief idea about the penalty that is charged.

Overview of Common Mistakes to Avoid

There are several common mistakes that taxpayers make when filing their self-assessment tax return. These mistakes include:

Failing to Register for Self-Assessment

Many taxpayers are not aware that they need to register for self-assessment. If you have not registered, you will not receive a notice to file your tax return, and you may be subject to penalties for not filing. To register for self-assessment, you need to visit the HMRC website and fill out the registration form.

Failing to Understand What Needs to Be Included in Your Self-Assessment Tax Return

Taxpayers need to include all their income and expenses related to their tax return. This includes income from employment, self-employment, property rental, and other sources. Common items that taxpayers forget to include in their tax returns are bank interest, tips, foreign income and pension contributions. It is essential to ensure that you include all relevant information in your tax return to avoid underreporting your income.

Failing to Keep Accurate Records

Keeping accurate records is crucial for filing your self-assessment tax return. Without accurate records, it can be difficult to fill out your tax return correctly, and you may miss out on claiming deductions and credits. Common record-keeping mistakes that taxpayers make are not keeping receipts, failing to record all expenses, and not keeping records up to date. To maintain accurate records, you should keep all invoices, receipts, bank statements, and other financial documents.

Failing to Claim All Available Deductions and Credits

Taxpayers may be eligible for various deductions and credits that can reduce their tax liability. Some common deductions and credits that taxpayers forget to claim are charitable donations, pension contributions, and business expenses. To ensure that you claim all available deductions and credits, you should keep accurate records of your expenses and also seek professional advice if necessary.

Failing to Meet the Filing Deadline

The deadline for filing your self-assessment tax return online is 31st January. If you miss the filing deadline, you may be subject to penalties and interest charges. Therefore, to ensure that you file your tax return on time, you should start early and seek professional advice if necessary.

Failing to Pay the Correct Amount of Tax

Paying the correct amount of tax is crucial to avoid penalties and interest charges. If you underpay your tax, you may be subject to fines and interest charges, which can quickly add up. Therefore it is important that your self-assessment tax return is properly calculated and filed.

Explanation of how to calculate the correct amount of tax owed

To calculate the correct amount of tax owed, you must first calculate your taxable income, taking into account any income from employment, self-employment, savings, investments, property rental and any other income applicable. You can then apply any relevant tax allowances and deductions, such as personal allowances, business expenses, and charitable donations.

Once you have calculated your taxable income, you can use the applicable tax rates and bands to calculate your tax liability. The tax rates and bands can vary depending on your income and personal circumstances.

Tips for ensuring you pay the correct amount of tax

  • To ensure that you pay the correct amount of tax, you should:
  • Keep accurate records of your income and expenses.
  • Use HMRC’s online tax calculator to estimate your tax liability.
  • Seek professional advice if you are unsure about any aspect of your tax return.
  • Check your tax calculation carefully before submitting your tax return.
  • Set up a payment plan with HMRC if you cannot afford to pay your tax bill in full by the due date.


Filing your self-assessment tax return accurately and on time requires careful attention to detail. By avoiding common mistakes such as failing to register for self-assessment, failing to keep accurate records, and failing to pay the correct amount of tax. You can ensure that the process runs smoothly. Seeking professional advice when needed can also provide peace of mind and ensure that you meet all of your needs. We are a group of accountants with an aim to take away the pain of tax filing. Book a session with one of our accountants to relieve you from your hassle.

Share This :

Leave a Comment

Your email address will not be published. Required fields are marked *

Recent Post

Dont Hesitate To Contact Us

We would love to hear from you.