A Guide To Tax Return Self Assessment

Discover an introductory guide to submitting a UK tax return self assessment from real tax and accountancy experts here in the UK!

Tax return self assessment is a crucial process for individuals to declare their income, claim deductions, and calculate their tax liability. This guide provides a comprehensive overview of the key elements involved in the self-assessment process, helping you navigate through the complexities of filling out a tax return self assessment. If you’d like some help with this however, don’t forget that you can reach out to our team of tax return experts for support no matter whether you’re submitting a self-assessment as an employed individual, or if you’re self employed.

A Step-by-Step Guide to Completing A Tax Return Self Assessment

Understanding Tax Return Self Assessment

Definition and Purpose

Self-assessment involves individuals taking responsibility for reporting their own income, and claiming relevant deductions to determine the tax they owe.

Who Needs to File a Self Assessment?

In the United Kingdom, the requirement to file a tax return self-assessment extends to individuals with specific financial circumstances. Generally, those who need to submit a self-assessment include self-employed individuals, business owners, and freelancers. Additionally, individuals with untaxed income, such as rental earnings or dividends, surpassing the set thresholds must also file a tax return. Moreover, high-income earners, individuals claiming substantial expenses, or those receiving foreign income are typically obligated to complete a self-assessment. Understanding whether you fall into any of these categories is crucial to ensuring compliance with HM Revenue & Customs (HMRC) regulations, and it paves the way for a smooth and timely submission of your tax return self-assessment.

The Basic Key Components of a Self Assessment

There are a number of basic but essential elements that combine to make up a self-assessment tax return. We’ll talk about each of them in more detail below, but in basic terms these components are your basic personal information, information regarding all of your sources of income, and details concerning any tax deductions or allowances to which you are entitled.

A Step-by-Step Guide to Completing A Tax Return Self Assessment

Do you want some help filing your tax return self assessment? No problem, click here!

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Step 1 - Your Personal Information

Among the very first things you’ll be asked to provide as part of a self assessment tax return  are your full name, address, and other basic contact details such as a telephone number and/or email address. You will also be asked for your National Insurance number, so it is useful to have all of these details to hand before you begin filling out your self assessment tax return - and of course, you should always make sure that any and all of the information that you provide here is true and accurate to the best of your knowledge.

A Step-by-Step Guide to Completing A Tax Return Self Assessment

Step 2:Income Declaration

At the income declaration stage you will be asked to provide details explaining where all of the money you earn (or otherwise receive) comes from. Typically these will fall into one of three categories, as defined below:

Employment Income

Unless you’re self-employed, a declaration of employment income should Include details of your salary, bonuses, and any other employment-related income.

Self-Employment Income:

If you are self-employed, then you need to make a declaration of self-employment income. As with ‘employment income’ above, here you should declare income earned through the business you earn and/or the freelance activities that you undertake.

Other Sources of Income:

Of course, a work salary is not the only way that a person can receive taxable income. As a result, here in the ‘other sources of income’ section is where you should declare any income you receive from investments, rental properties, and any other similar sources.

A Step-by-Step Guide to Completing A Tax Return Self Assessment

Step 3: Deductions and Allowances

Just as there are many different types of taxable income, there are also a number of different tax ‘breaks’ that a person can be in receipt of. These are known as deductions and allowances, and - depending on the specific deduction or allowance concerned - either cannot be taxed, or are taxed at a lower rate.

Common Deductions:

Common deductions include things like business expenses, student loan interest, and charitable contributions.

Tax-Free Allowances:

In the UK, tax-free allowances refer to specific amounts of income that individuals can earn without incurring tax liabilities. Examples of tax-free allowances include the Personal Allowance, or the tax-free allowance on savings interest, where a portion of interest income from savings accounts remains untaxed.

A Step-by-Step Guide to Completing A Tax Return Self Assessment

Step 4: Calculating and Paying Taxes

The Tax Calculation Process:

As we’ve seen, in the UK the tax calculation process for self-assessment involves a systematic evaluation of various income sources, deductions, and allowances to determine an individual’s final tax liability. People submitting a tax return self assessment need to declare their income, including earnings from employment, self-employment, and any other sources, such as rental income or dividends.

Once the total income is established, allowable deductions, such as business expenses or charitable contributions, are factored in. Subsequently, individuals benefit from tax-free allowances, like the Personal Allowance, reducing the taxable income. The remaining amount is then subjected to the applicable income tax rates, ranging from basic to higher and additional rates depending on income brackets.

Understanding this process is pivotal for accurate reporting and ensures that taxpayers fulfil their financial obligations while optimising available exemptions and reliefs. Additionally, the use of online tools (more on those later) can simplify the calculation process and enhance the accuracy of self-assessment tax returns.

Payment Options:

For individuals navigating the self-assessment process in the UK, understanding the various payment options is paramount to fulfilling their tax obligations correctly. HM Revenue & Customs (HMRC) provides several convenient methods for settling tax liabilities.

One common avenue is online payment through the HMRC website, allowing taxpayers to use debit or credit cards. However, bank transfers and cheque payments remain popular and viable alternatives for those who prefer traditional methods. It's essential to be mindful of the options and ensure that the payment method you choose fits in with your personal financial preferences - if so, it only makes things easier.

A Step-by-Step Guide to Completing A Tax Return Self Assessment

Important Deadlines and Penalties

Submission Deadlines:

You should of course be aware of the relevant deadlines for filing your tax return. In 2024 these include January 31st, which is the final day when self assessment tax returns may be filed, and April 5th, which is the final day of the tax year. If you’ve never filed a tax return self assessment before, you also need to inform HMRC of your intention to do so by October 5 of the year before.

Penalties That May Be Incurred:

If you submit your tax return self assessment late, then you may incur one of a range of penalties, depending on the circumstances or reasons for the late submission, and how late that submission is. For more details on these penalties, take a look at this page from HMRC.

A Step-by-Step Guide to Completing A Tax Return Self Assessment

Further Resources and Support

HM Revenue & Customs (HMRC) Assistance:

For a thorough overview of tax return self assessments direct from the UK Government body to which you must report them, please see this page.

Online Tools and Calculators:

There are a number of different online tax calculation tools just like this one that can help you calculate how much tax you need to pay, based on the income amounts that you provide them with.

Seeking Professional Advice:

If you prefer to deal with a real human being when it comes to your tax return self assessment, then don’t forget that our team is available to provide a range of advice and support around your tax return and how to ensure that you get it done right.

A Step-by-Step Guide to Completing A Tax Return Self Assessment


In conclusion, this guide serves as a comprehensive resource to navigate the intricacies of tax return self assessment. By following the step-by-step process and understanding common challenges, you can ensure a smooth and accurate filing experience. Remember to leverage available resources and seek professional advice when needed, as that expert insight can be a valuable tool in helping you avoid penalties and enjoying a hassle-free submission experience.

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