Understanding Self Assessment

Tax season can daunting, with endless forms, deadlines, and regulations to decipher. Amidst this complexity lies the self-assessment process—a crucial step for individuals in the UK to fulfil their tax obligations. But what exactly is self-assessment, and how does it work?

2 April 2024
Reading time
Around 4 min
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Demystifying Self Assessment

At its core, self-assessment is a system implemented by HM Revenue and Customs (HMRC) in the UK, allowing individuals to report their income, capital gains, and any other relevant financial details to determine their tax liability. Unlike traditional methods where employers deduct tax automatically from salaries, self-assessment places the onus on the individual to calculate and report their own tax liability.

The Process Unveiled

The self-assessment process typically unfolds in several stages:

  • Gathering Information: The first step involves collecting all relevant financial documents, including income statements, bank statements, and receipts for deductible expenses.

  • Completing the Return: Armed with this information, individuals then complete their self-assessment tax return, providing accurate details of their income, gains, and allowable deductions.

  • Filing the Return: Once the return is complete, it must be filed with HMRC by the annual deadline, usually by 31st January following the end of the tax year.

  • Paying Tax Due: Individuals are also responsible for paying any tax due by the same deadline to avoid penalties and interest charges.

Simplify Your Self-Assessment Journey with Finance Box

Navigating the self-assessment process can be daunting, but with the right support, it becomes a manageable task. At Finance Box, we're here to guide you through every step of the journey, offering a streamlined and stress-free experience.

Through our online portal, we ask you a short questionnaire and offer you an opportunity to upload a number of documents to evidence the numbers we need. Here's how it works:

  • Complete Our Questionnaire: Access our user-friendly portal and complete the questionnaire tailored to your specific tax situation.

  • Upload Evidence Documents: As you progress through the portal, upload any necessary evidence documents as prompted, ensuring accuracy and completeness. This may be P60’s from any payrolls, dividend certificates, bank interest statements, sole trader accounts.

  • Review and Approval: Our expert team will then draft your tax return based on the information provided. Once complete, we'll send it to you for review and approval.

  • Effortless Filing: Upon approval, we'll file your tax return directly with HMRC, ensuring compliance with all regulatory requirements. We'll also guide you through the process of paying any tax due, helping you avoid last-minute stress and penalties.

Important Dates to remember:

  • The Tax year will be 6th April till the 5th April of the following year

  • By 31st January following the tax year end, the filing is due.

  • Any balance due should also be paid by the same 31st January.

  • 50% on account for the next year should also be paid by 31st January (but now, 10 months of the next year will already have been passed). This amount comes off your next tax bill.

  • A second 50% on account is due to be paid by 31st July. This amount comes off your next tax bill.

Ready to Simplify Your Self-Assessment?

Don't let the complexities of self-assessment overwhelm you. With Finance Box by your side, navigating tax season becomes a breeze. We’ll normally be in touch in June each year to remind you that it’s time to start this. Visit our portal at financebox.senta.co to begin your self-assessment journey today. Let us handle the intricacies while you focus on what matters most.


Knowing your tax return and/or filing it early doesn’t mean that you need to pay it early. In fact you get the advantage of knowing what’s coming. So don’t delay.