Every year, more than 12 million people in the UK are required to submit a Self Assessment tax return to HMRC. If you are one of them, the process can feel overwhelming, especially if you are filing for the first time or your financial circumstances have changed. The good news is that most of the difficulty comes from not knowing what to expect rather than from the filing itself.
This guide sets out exactly who needs to file a personal tax return, which documents you should pull together before you start, what the key deadlines look like, and why returns commonly end up delayed or corrected.
Whether you are self-employed, a landlord, a company director, or someone with untaxed investment income, the aim here is to give you a clear picture of what lies ahead so you can file with confidence.
Who Needs to File a Personal Tax Return?
Not everyone in the UK needs to complete a Self Assessment return. If your only source of income is a salary taxed through PAYE and you have no additional earnings, HMRC does not require you to file one. The obligation kicks in once your income or financial situation falls outside what PAYE can handle on its own.
You will need to file a personal tax return if you are self-employed as a sole trader and your gross income exceeded £1,000 during the tax year. The same applies if you are a partner in a business partnership or a director of a limited company. Landlords receiving rental income must also file, as do individuals who earned untaxed income from savings, dividends, or investments above their personal allowances.
There are less obvious triggers too. If you received foreign income, made capital gains from selling shares, property, or crypto assets above the annual exempt amount, or you need to pay the High Income Child Benefit Charge, HMRC expects a return from you. The same applies if HMRC has issued you a notice to file, which means you must submit a return regardless of whether you think you owe anything.
If you are unsure whether you fall into any of these categories, HMRC provides an online tool that can help you check. Registering unnecessarily is not ideal, but failing to register when required carries penalties, so it is better to check sooner rather than later.
Key Deadlines You Should Know
The UK tax year runs from 6 April to 5 April the following year. For the 2024/25 tax year, the relevant deadlines are as follows.
| Deadline | What It Covers |
| 5 October 2025 | Register for Self Assessment for the first time. HMRC needs this time to issue your Unique Taxpayer Reference (UTR) and set up your account. |
| 31 October 2025 | Paper tax returns must reach HMRC by midnight on this date. |
| 30 December 2025 | File your online return by this date if you want tax owed (under £3,000) collected through your PAYE tax code. |
| 31 January 2026 | Online tax returns must be submitted and any tax owed must be paid by midnight. Missing this triggers an automatic £100 penalty, even if you do not owe any tax or have already paid what is due. |
| 31 July 2026 | Second payment on account deadline. These are advance payments towards your next year’s tax bill, typically required when your previous Self Assessment showed tax of £1,000 or more that was not collected through PAYE. |
The penalties escalate quickly after the initial £100 fine. After three months, daily penalties of £10 per day apply for up to 90 days. After six months, a further charge of 5% of the tax due or £300 (whichever is greater) is added. Twelve months of non-filing can result in even steeper charges.
The message is straightforward: file on time, even if you cannot pay immediately. HMRC offers time-to-pay arrangements for those who need them, but only if you make contact before the deadline passes.
Documents and Records You Need to Gather
Preparation is the single biggest factor in whether your return goes smoothly or turns into a last-minute scramble. Before you sit down to fill in any boxes, make sure you have the following records to hand.
Your UTR and Government Gateway Details
Your 10-digit Unique Taxpayer Reference is essential for filing. If you have not yet registered, you will need to do so through HMRC’s online service. Our guide on how to register for Self Assessment with HMRC walks through the process step by step. Once registered, you will use your Government Gateway account to access the online filing system. Keep your login credentials somewhere secure, as you will need them every year.
Income from Employment or Self-Employment
If you are employed, your P60 from your employer summarises the pay and tax deducted during the year. If you left a job partway through the year, your P45 serves the same purpose for that period of employment. For those with multiple employers, you will need a P60 or P45 from each one.
Self-employed individuals need full records of all invoices raised, sales made, and business expenses incurred. Bank statements should be reconciled against these records so there are no gaps.
If you use cloud accounting software such as Xero, much of this will already be organised for you, but it is still worth reviewing the figures before filing. Allowable expenses for sole traders include costs that are wholly and exclusively for business use, such as office supplies, travel, professional subscriptions, and a proportion of home office costs if you work from home.
Rental Income and Property Records
Landlords need tenancy agreements, rental statements from letting agents, and receipts for any property-related expenses. Allowable costs include repairs and maintenance, letting agent fees, insurance premiums, and the finance cost element of mortgage interest payments.
Be careful to distinguish between genuine repairs (which are allowable) and capital improvements (which are not deductible against rental income). Getting this distinction wrong is one of the most frequent mistakes HMRC flags on property returns.
Savings, Investments, and Capital Gains
Banks and building societies issue annual summaries showing the interest you have earned. Investment platforms provide dividend statements and, where applicable, capital gains reports. If you sold shares, property, or crypto assets during the year, you will need to calculate the gain or loss on each disposal. The annual exempt amount for capital gains tax has been significantly reduced in recent years, which means more people are now caught by reporting requirements than before.
If you hold investments overseas or receive foreign income, you may also need to report this on the foreign pages of your return. Any tax paid abroad may be eligible for double taxation relief, but you will need documentation to support this claim.
Pension Contributions and Gift Aid
If you made personal pension contributions during the year, these can reduce your overall tax liability. Higher-rate and additional-rate taxpayers in particular benefit from claiming the additional relief through Self Assessment, since only basic-rate relief is given automatically by the pension provider.
Gift Aid donations to registered charities also affect your tax position. If you are a higher-rate taxpayer, you can claim additional relief on Gift Aid payments through your return. Keep records of all donations and the Gift Aid declarations you signed.
Common Reasons Returns Get Delayed or Corrected
Delays and corrections are almost always avoidable. The most common causes include missing or incomplete information, mathematical errors, and misunderstanding which expenses are allowable. Our Self Assessment tax return guide for the 2024/25 year covers the filing process in full, but the mistakes below are worth highlighting on their own.
Forgetting to include a source of income is the single most common error. HMRC receives information from employers, banks, investment platforms, and pension providers. If your return does not match these records, HMRC will open an enquiry or issue an amended calculation. Even small amounts of untaxed interest or a freelance payment you forgot about can create problems.
Claiming expenses that do not qualify is another frequent issue. Personal costs mixed in with business expenses, estimated figures without supporting receipts, and treating capital expenditure as a revenue deduction all attract scrutiny. For landlords, one of the most common pitfalls is claiming the full mortgage payment rather than just the allowable finance cost element.
Leaving filing to the last minute also creates risk. If you discover a missing document on 30 January, you have very little room to resolve it before the deadline. Filing early gives you time to identify gaps, ask questions, and correct errors without penalty pressure.
How to Reduce the Risk of Errors
Good record-keeping throughout the year is the best defence against errors at filing time. HMRC requires you to keep records for at least five years after the 31 January submission deadline, so it is worth establishing a system early. Cloud-based accounting tools make this significantly easier by capturing transactions in real time and categorising them automatically.
If your tax affairs are relatively straightforward, HMRC’s online service will walk you through each section of the return and perform basic calculations for you. For anything more complex, such as multiple income sources, foreign income, capital gains on several disposals, or a mix of employment and self-employment, professional support can save you both time and money.
A qualified accountant will not only prepare and submit your return accurately but will also identify reliefs and allowances you may not have considered. Many people who file their own returns end up overpaying simply because they were unaware of a deduction they were entitled to.
It is also worth noting that from April 2026, sole traders and landlords with a turnover above £50,000 will be required to use Making Tax Digital for Income Tax. This means quarterly digital updates to HMRC rather than a single annual return. If your turnover is approaching this threshold, it makes sense to start using MTD-compatible software now so the transition is as smooth as possible.
What Happens After You File
Once your return has been submitted, HMRC will send you a calculation confirming how much tax you owe or whether you are due a refund. If you filed online, this calculation is usually available immediately. Check it carefully against your own figures to make sure everything lines up.
If you owe tax, you can pay through a range of methods, including online banking, debit card, or the HMRC app. If your bill is under £3,000 and you file your online return by 30 December, you may be able to have the amount collected through your PAYE tax code the following year, spreading the cost across your monthly pay. For larger amounts, HMRC’s time-to-pay service allows you to spread payments over up to 12 months, provided you set this up before the deadline.
HMRC can open an enquiry into your return for up to 12 months after the filing deadline. This does not necessarily mean you have done anything wrong, as some enquiries are random checks. Having clear, well-organised records makes the process far less stressful if it happens to you.
Working With an Accountant on Your Personal Tax Return
There is a common misconception that accountants are only for businesses or high earners. In practice, anyone filing a Self Assessment return can benefit from professional support, particularly if your circumstances are not entirely straightforward. A good sole trader accountant will make sure your return is accurate and filed on time and that you are claiming every deduction and relief available to you. They can also flag potential issues before they become problems, such as approaching the VAT registration threshold or structuring your income more efficiently.
For those who prefer to handle their own return, an accountant can still add value through a one-off review before submission. A fresh pair of qualified eyes can catch mistakes that are easy to miss when you have been staring at the same figures for hours.
Get Your Personal Tax Return Filed Right
If you want your Self Assessment handled properly from start to finish, the team at eAccounts can take it off your hands. As Chartered Accountants and Xero Platinum Partners, we prepare and submit personal tax returns for sole traders, landlords, company directors, and individuals with complex tax affairs across the UK.
Every client gets a dedicated accountant who knows their file inside out. Get an instant quote in under two minutes, call us on 029 2105 5592 to speak with one of our team, or visit our accountants near me page to see how we can support you.
FAQs
Do I need to file a personal tax return if I am employed and earn under £100,000?
If your only income is a salary taxed through PAYE and you have no other untaxed earnings, you generally do not need to file. However, if you receive rental income, investment income above your allowances, or you need to pay the High Income Child Benefit Charge, you will still need to submit a Self Assessment return regardless of your salary level.
What happens if I file my tax return late but do not owe any tax?
HMRC will still issue a £100 late filing penalty even if your tax bill is zero. The penalty is for missing the deadline itself, not for failing to pay. If the return remains outstanding for longer, additional penalties will continue to build.
Can I amend my tax return after submitting it?
Yes. You can amend your Self Assessment return within 12 months of the original 31 January filing deadline. For example, a return filed for the 2024/25 tax year can be corrected up until 31 January 2027. After that window closes, you will need to write to HMRC to request any changes.
How long do I need to keep my tax records?
HMRC requires you to keep all records and supporting documents for at least five years after the 31 January submission deadline. If you are self-employed, this means holding on to invoices, receipts, bank statements, and expense records for a minimum of five years and ten months from the end of the tax year they relate to.
Is it worth using an accountant for a straightforward personal tax return?
Even relatively simple returns can benefit from a professional review. An accountant can identify reliefs and allowances you may not be aware of, such as additional pension tax relief for higher-rate taxpayers or allowable expenses you have overlooked. The cost of an accountant often pays for itself through a lower tax bill and the peace of mind that your return has been filed correctly.
