Self Assessment Tax Return Deadline: How to File a Tax Return

The Self Assessment tax return deadline is looming, as the 31st January creeps ever closer. But what exactly does this deadline mean? Does a Self Assessment tax return even apply to you? And, if it does,…

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Last Updated: 23rd March 2023

The Self Assessment tax return deadline is looming, as the 31st January creeps ever closer. But what exactly does this deadline mean? Does a Self Assessment tax return even apply to you? And, if it does, how do you file tax returns correctly?

Here, GoSimpleTax tells you everything you’d like to know about the Self Assessment tax return deadline – and how you can take the right steps to fill it out accurately and successfully.


The eligibility criteria for those required to complete a Self Assessment is simple: it’s for anyone who earns income outside of PAYE (Pay As You Earn), has PAYE income between £50,000 and £60,000 and receipt of child benefit or simply has PAYE income over £100k.

Many UK employees pay their tax and National Insurance contributions solely via PAYE. Their employer deducts all the necessary tax due from their wage, making the right calculations based on what they earn.
However, any income outside of PAYE must be declared via a Self Assessment form, which needs to be filled by the person who generates the income.

This can be money earned through self-employed work, property rental income and more. Our software contains all the necessary Self Assessment forms, which can be automatically filled with your income information.

When Is the Deadline for the Self Assessment Tax Return?

The Self Assessment tax return deadline is the 31st January. By then, the tax return must be sent to HMRC so they can determine how much tax and National Insurance you are liable to pay. Please note that HMRC do not advise on where you can gain tax relief. You’ll have to determine these areas for yourself, or use tax software like GoSimpleTax to find that information for you.

It’s important to be aware of the deadline date, as filing a late tax return will result in fines. There are, however, as many as four different ways to send this information to HMRC every year.


As the Self Assessment tax return deadline approaches, it’s worth reviewing your options so you can determine which submission method is best given your circumstances.


The Self Assessment tax return deadline for paper submissions is the 31st October, but it’s worth noting that these types of tax submissions are being phased out. Plus, whilst paper returns don’t require an internet connection, they are invariably time-consuming and complicated.


Heading to HMRC’s official website is another way to submit your form in time for the Self Assessment tax return deadline. First, you’ll need to register for your Government Gateway login. Without this, you cannot submit your tax return via the HMRC website.

Like paper returns, this method of tax submission will soon be phased out, although it currently remains a popular option.


Accountants are armed with the specialist knowledge and tools required to complete your tax return for you, ensuring it reaches HMRC before the Self Assessment tax return deadline.

Whilst accountants offer support and guidance as they complete all the calculations for you, they often charge a considerable amount of money for the privilege. You’ll spend at least £150 on a typical Self Assessment service. Using software instead can be far more cost-effective, especially if you’re a part-time freelancer or contractor.


Arguably the best way to meet the Self Assessment tax return deadline is to take advantage of tax return software: a system that sorts through the required information that you provide, and performs every necessary calculation! It also shows you all relevant sections that apply to your personal tax affairs, and sends the complete information directly to HMRC.

With GoSimpleTax, you can relax in the knowledge that you’ll meet the Self Assessment tax return deadline without any problems. We’re HMRC-recognised and have won several awards for our service.

Best of all, you can start using our platform without paying a single penny. Our free trial allows you to complete and calculate your tax return using inputted income and expenditure information. Then, when you’re ready to submit it, all you need to do is upgrade your account. Discover how to file a Self Assessment tax return the easy way today.

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Blog content is for information purposes and over time may become outdated, although we do strive to keep it current. It's written to help you understand your Tax's and is not to be relied upon as professional accounting, tax and legal advice due to differences in everyone's circumstances. For additional help please contact our support team or HMRC.

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