6 April – Start of the Tax Year
Each year, 6 April marks the beginning of the UK’s new financial year. From this point forward, any income you earn or expenses you incur will apply to the 2025/26 tax year.
One of the most important elements to check early in the year is your tax code. Issued by HMRC, your tax code determines the amount of tax-free income you are allowed and directly affects how much tax is deducted from your income. For the 2025/26 tax year, the standard Personal Allowance remains at £12,570. This means that the first £12,570 of your income is not subject to Income Tax, unless changes are made by the government later in the year.
If your tax code is incorrect, you may pay too much or too little tax, potentially resulting in an unexpected bill or the need to claim a refund. It’s important to confirm your tax code as soon as possible to avoid such issues.
Importance of Early Preparation
Although the final deadline for submitting your Self Assessment tax return is months away, it’s a wise move to begin organising your financial paperwork early in the tax year. Whether you file your return yourself or work with an accountant, having your documents ready makes the process significantly smoother.
Start by gathering all relevant income sources and expense records, including receipts, invoices, dividend statements, savings interest, rental income details, and pension information. If you are self-employed, keeping digital copies of these documents throughout the year can save a lot of time and prevent errors when it comes to filing.
Being prepared also allows you to assess your potential tax liability early and budget for any payments due. If you expect to owe a significant amount, knowing this in advance gives you time to save and avoid a financial strain in January.
Income Types That May Require Self Assessment
Not all income is taxed at source. If you earn money outside of a regular PAYE salary, you may be required to file a Self Assessment tax return. Common income sources that require reporting include:
- Self-employment or freelance income
- Rental income from property
- Dividends and investment earnings
- Interest from savings accounts
- Pensions and annuities
- Foreign income
- Employment benefits not fully taxed through PAYE
- Trust income
If you receive any of the above, you need to keep thorough records and be aware of how they are taxed. You should also be aware of the various tax bands and thresholds to determine your applicable tax rate.
Keeping Track of Business Expenses
If you’re self-employed, you may be able to reduce your tax bill by claiming allowable business expenses. These include costs such as:
- Office supplies and equipment
- Travel expenses for business purposes
- Marketing and advertising
- Subscriptions and professional memberships
- Utilities and internet costs if working from home
Only expenses that are exclusively for business use are claimable, so accurate record-keeping is vital. Claiming these costs appropriately will help lower your taxable profit and reduce the amount you owe.
Benefits of Organised Record-Keeping
One of the most effective ways to manage your tax obligations is by maintaining a consistent and accurate system for tracking income and expenses. Whether you use spreadsheets or accounting software, having real-time access to your financial information can help you stay in control.
Digital record-keeping also supports compliance with HMRC’s Making Tax Digital initiative, which is gradually rolling out to more taxpayers. Keeping clean records makes it easier to spot mistakes, verify amounts, and respond quickly if HMRC raises a query.
Planning Ahead for Tax Bills
Many taxpayers fall into the trap of leaving their Self Assessment until the last minute, only to discover a large tax bill with little time to pay. To avoid this scenario, it’s important to run estimated calculations well in advance.
If you use a digital tool or software that estimates your tax liability as you go, you can plan monthly savings to cover the eventual amount due. This proactive approach prevents surprises and spreads the financial burden.
Understanding Changes That May Affect Your Tax Position
Throughout the tax year, HMRC and the government may announce changes to allowances, thresholds, or available deductions. Staying informed of these updates helps ensure you remain compliant and can take advantage of any new reliefs or tax-saving opportunities.
It’s advisable to subscribe to official HMRC updates or check in periodically with financial news outlets. This is especially important if you are nearing the edge of a tax band or are expecting major changes to your income.
Considerations for the Newly Self-Employed
If you’ve recently become self-employed, the beginning of a new tax year is the ideal time to ensure you’ve registered for a Self Assessment and understand what’s required.
You’ll need to register with HMRC if this is your first time filing, and you’ll be issued a Unique Taxpayer Reference (UTR). Once registered, you can begin tracking income and expenses, ensuring you’ll have everything you need when it’s time to file.
Registering early allows you to set up digital access to HMRC’s online services, link your business bank account, and avoid late registration penalties. Waiting until close to the registration deadline could delay your ability to submit your tax return on time.
Common Pitfalls to Avoid Early in the Tax Year
Several mistakes often catch people out at the start of the financial year, including:
- Failing to check or update tax codes
- Ignoring small sources of income that still require reporting
- Overlooking changes in employment status
- Underestimating tax liability due to inaccurate records
By taking time in April and May to verify your situation, you can significantly reduce the chance of facing penalties or unexpected bills later.
Role of Digital Tools in Simplifying Tax Obligations
Using digital accounting tools can simplify the tax preparation process by automating record-keeping, categorising transactions, and tracking income in real time. These tools can also generate estimates of your tax owed and help prepare the information in a format that aligns with HMRC’s Self Assessment requirements.
As HMRC continues to expand its Making Tax Digital initiative, familiarity with these platforms will soon become a necessity rather than a choice. Embracing them early in the tax year ensures a smoother experience.
Why the Start of the Year Sets the Tone
Ultimately, the beginning of the tax year is the best time to take a fresh approach to your finances. Whether you’re a seasoned freelancer or starting out in business, getting your affairs in order from day one allows you to take advantage of allowances, avoid stress, and plan for any liabilities ahead.
With the right preparation and a consistent routine, the Self Assessment process becomes less of a burden and more of a manageable annual task.
Meeting Mid-Year Tax Deadlines: 31 July and 5 October Explained
As the 2025/26 tax year progresses, two mid-year deadlines become central for UK taxpayers navigating the Self Assessment process: 31 July and 5 October. Each of these dates carries specific obligations that can significantly impact your financial planning and tax compliance.
31 July is the deadline for the second payment on account, a critical payment for those who are self-employed or who earn untaxed income. Meanwhile, 5 October marks the deadline to register for Self Assessment if you are newly self-employed or earning other forms of untaxed income. Failing to meet either can lead to interest charges, penalties, or delays that complicate your financial year.
Understanding the Payment on Account System
The payment on account system is designed to help spread the cost of your Income Tax bill. Rather than paying your entire tax liability in a single lump sum in January, the system divides your estimated tax into two payments: one in January and the second in July.
Each payment is typically equal to 50% of your previous year’s tax bill. For example, if your total tax due for 2024/25 was £4,000, you would pay £2,000 in January 2025 and another £2,000 in July 2025. The actual liability for the current year is reconciled after the return is submitted.
If your actual income in 2025/26 ends up being higher than the year before, you may need to make a ‘balancing payment’ in January 2026. Conversely, if your earnings are lower, you may receive a refund or a credit against future tax.
Who Needs to Make Payments on Account?
Payments on account generally apply if your last Self Assessment tax bill was over £1,000 and less than 80% of your tax was collected at source, such as through PAYE. It is most common among sole traders, landlords, and those with substantial savings income.
It’s important to understand whether this applies to you, as missing the July deadline results in interest charges from HMRC. To avoid unnecessary costs, check your previous Self Assessment return and calculate what your second payment should be.
How to Pay by 31 July
There are multiple ways to make your second payment on account:
- Online through your HMRC personal tax account
- By BACS or Faster Payments from your online banking
- Through a debit card
- Sending a cheque via post (less common now)
Be sure to allow time for the payment to clear, especially if you are using postal methods or paying close to the deadline. HMRC considers the payment date as the day they receive the funds, not the day you send them.
Adjusting Your Payments if Your Income Changes
If your earnings have decreased and you anticipate owing less tax than the previous year, you can request to reduce your payments on account. This can be done online or by submitting form SA303.
However, if you reduce your payments too much and end up underpaying, HMRC will charge you interest on the shortfall. It’s essential to make a realistic estimate of your expected earnings before choosing this option.
Role of Accurate Bookkeeping
Having accurate and up-to-date financial records throughout the year makes it easier to predict your current tax obligations and decide whether to adjust your payments. Timely bookkeeping ensures that your earnings and expenses are always current, supporting better forecasting.
Regularly reconciling your accounts allows you to track whether your income is trending higher or lower than the previous year. With this insight, you can make informed decisions about payments on account and avoid surprises in January.
Planning Ahead for the January Payment
Even though 31 July is a major deadline, you must still prepare for the final payment and tax return due on 31 January. If your actual tax due is more than your two advance payments, you’ll owe a balancing payment in January.
Planning ahead means budgeting for this potential shortfall. If your income has increased, it’s wise to set aside extra funds to cover the difference rather than relying on the assumption that your previous tax amount will cover it.
Introducing the 5 October Deadline
While July focuses on payments, October is about registration. If you’ve recently started earning income that hasn’t been taxed at source, 5 October is the final date to register for Self Assessment.
This deadline applies to:
- Newly self-employed individuals
- People with rental income
- Those earning from investments or savings interest
- Individuals receiving income from trusts, pensions, or abroad
Failure to register on time could result in penalties or delayed issuance of your Unique Taxpayer Reference (UTR), which you need in order to file your return.
How to Register for Self Assessment
Registration varies based on your employment status:
- If you’re self-employed and submitting for the first time, you must register online through HMRC’s dedicated portal. HMRC will then issue your UTR and activation code for your account.
- If you’ve previously submitted as self-employed but took a break, you can reactivate your status by submitting a CWF1 form.
- If you’re not self-employed but have income requiring declaration, you should complete the SA1 form.
Once registered, you will be set up with an online account where you can file returns, track payments, and view your tax history.
What Happens After Registration?
After you register, HMRC will send you a letter confirming your UTR. This unique number identifies your tax records and is required for submitting your Self Assessment. You’ll also receive information about setting up your digital tax account, which becomes the hub for managing all tax-related submissions and communications.
From this point, you should begin compiling your income and expense records for the year. Although your return won’t be due until January, having these details in place early ensures smoother filing later.
Key Tips for New Self Assessment Filers
If you’re new to the Self Assessment system, there are a few practical steps to help simplify the process:
- Set aside time each month to update your records
- Keep receipts and invoices organised by category
- Maintain a separate business bank account
- Track any home office or vehicle expenses
- Learn what tax reliefs and allowances may apply to you
The more structured your approach, the easier the filing process becomes. Many first-time filers underestimate the level of detail required, leading to last-minute stress.
Avoiding Registration Pitfalls
Common mistakes around registration include:
- Missing the 5 October deadline
- Registering under the wrong category
- Failing to respond to HMRC’s activation letter
- Forgetting to set up your digital account
These oversights can delay your ability to file and potentially result in late filing penalties. By registering early, you leave room to correct any errors and seek support if needed.
Staying Informed Through the Year
Tax responsibilities don’t end after July or October. Mid-year is the ideal time to review your financial situation, ensure you’re on track with savings for upcoming payments, and check for any regulatory changes.
Use this time to adjust your budget, review your estimated tax liability, and explore opportunities to lower your taxable income through allowances or deductions.
Final Milestones in the Tax Calendar: 31 October and 31 January Deadlines
As the 2025/26 tax year moves into its final stages, the focus for many UK taxpayers shifts to two major deadlines: 31 October and 31 January. These dates play a critical role in ensuring tax returns are submitted correctly and any payments owed to HMRC are made on time. Understanding the implications of these deadlines can help avoid penalties and ease the stress of last-minute filing.
The 31 October deadline applies to those who still submit their Self Assessment tax returns via paper, while 31 January is the final date for filing online returns and settling any outstanding tax for the previous tax year. Despite a growing push toward digital submission, a number of individuals still prefer the traditional paper route. However, both methods demand accurate preparation and awareness of what is required.
The 31 October Paper Filing Deadline
For taxpayers who choose to file their Self Assessment using a paper form, 31 October is the critical cut-off date. This means that all required forms and documents must reach HMRC by this date to be considered on time.
Submitting a paper return is still an option for those who prefer physical paperwork or lack access to digital tools. However, it’s important to note that this method is becoming increasingly outdated, and HMRC is gradually shifting all tax processes online.
Paper filing requires sending your completed SA100 form and any supplementary pages that apply to your income sources. These must be filled out accurately, as mistakes can result in delays or penalties.
Risks of Missing the Paper Deadline
Failing to meet the 31 October deadline means you’ll no longer be able to submit via paper and will need to file online instead. While this provides an extra three months, switching to digital at the last minute can present challenges if you’re unfamiliar with the online system.
Moreover, if you continue to submit by post and your return arrives late, HMRC will apply an immediate penalty. The initial fine for late filing is £100, regardless of whether you owe tax or not.
Filing a Paper Return Correctly
Accuracy is critical when submitting by post. Here are some steps to ensure your return is filled out correctly:
- Use the official SA100 form issued by HMRC
- Write legibly and use black ink if completing by hand
- Include all supplementary pages relevant to your income (e.g., SA103 for self-employment)
- Double-check your National Insurance number and Unique Taxpayer Reference (UTR)
- Ensure the form is signed and dated
Mail your return with sufficient time to allow for delivery. Consider using a tracked or recorded delivery method to confirm HMRC receives it on time.
Preparing for Online Submission
Whether you’re new to online filing or switching from paper, preparing early can make the process easier. Online returns are completed through your HMRC online account, where you can access the digital Self Assessment system.
Before starting, make sure your records are complete and up to date. This includes:
- Invoices and receipts for self-employment or freelance income
- Interest statements from banks or building societies
- Rental income details and associated expenses
- Pension and investment income
- Records of any capital gains or losses
Gathering these documents in advance helps streamline the process and reduces the likelihood of errors.
Benefits of Filing Online
Filing online offers several advantages over paper submission:
- Extra time: the deadline is extended to 31 January
- Immediate confirmation from HMRC upon submission
- Built-in error checks to reduce mistakes
- Automatic calculations of your tax liability
- Ability to amend your return if needed after filing
Online submission is also more secure and environmentally friendly. With HMRC’s digital infrastructure constantly improving, the experience is becoming more user-friendly each year.
31 January – The Final Deadline for Filing and Payment
The most significant tax date for the majority of UK taxpayers is 31 January. This is the last day to:
- Submit your Self Assessment tax return online for the 2024/25 tax year
- Pay any outstanding tax owed for that period
- Make your first payment on account for the 2025/26 tax year (if applicable)
Meeting this deadline is crucial to avoid penalties and interest charges.
Calculating and Paying Your Tax Bill
Once your return is filed, HMRC will calculate your final tax bill, or you can calculate it as you complete your return. Payment must be made in full by 31 January, unless you’ve arranged a payment plan in advance.
There are several ways to make payment:
- Online banking using your UTR as the payment reference
- HMRC’s online payment portal
- By debit card
- Through a pre-authorised direct debit
Late payments result in interest being charged from 1 February, so it’s vital to plan ahead.
Understanding Balancing Payments and Payments on Account
If you made payments on account in July and January based on your previous tax year’s earnings, your final bill may include a balancing payment. This occurs when your actual earnings exceeded last year’s estimate, and you owe more tax.
At the same time, if your tax bill exceeds £1,000 and less than 80% of your tax is collected at source, you may also need to make your first payment on account for the 2025/26 tax year. This can significantly increase the amount due in January, so early calculation and budgeting are essential to avoid cash flow issues.
Common Errors to Avoid When Filing
To ensure a smooth submission process, watch out for these common mistakes:
- Using incorrect figures or outdated forms
- Failing to include all sources of income
- Omitting claimable expenses or reliefs
- Entering the wrong UTR or National Insurance number
- Forgetting to hit ‘submit’ after completing the form
Double-check every section before submitting to reduce the risk of errors and potential follow-up from HMRC.
When and How to Amend a Return
If you discover an error after submitting your return, you can make amendments online up to 12 months after the 31 January deadline. Log into your HMRC account, navigate to your Self Assessment section, and select the return you wish to amend.
If the deadline for amendments has passed, you will need to write to HMRC explaining the mistake. Corrections may result in additional payments or refunds, depending on the nature of the adjustment.
Penalties for Late Filing or Payment
HMRC enforces strict penalties for late filing and payment. For late returns:
- An initial £100 penalty applies the day after the deadline
- Additional penalties accrue after 3, 6, and 12 months
For late payments:
- Daily interest charges begin accruing from 1 February
- A 5% penalty is added after 30 days, another after 6 months, and again after 12 months
These penalties can escalate quickly, so prompt action is important.
Planning Ahead for the Next Tax Year
While January marks the end of the previous tax cycle, it also provides an opportunity to start fresh for the new one. By setting up systems now for tracking income and expenses, you can simplify next year’s return.
Consider:
- Monthly check-ins to update financial records
- Using accounting software to categorise transactions
- Setting up reminders for upcoming tax dates
- Keeping digital copies of all receipts and invoices
These practices help maintain consistency and reduce the year-end scramble.
Seeking Help When Needed
If you encounter problems during the filing process, HMRC provides a variety of resources, including guides, calculators, and contact helplines. Independent advisors and tax professionals can also offer guidance tailored to your circumstances.
Seeking help early ensures you get the support you need before deadlines approach, reducing the risk of filing late or incorrectly.
Conclusion
As the 2025/26 tax year unfolds, being mindful of key dates is more than a matter of compliance—it’s a financial strategy. Starting with the 6 April reset, taxpayers have the opportunity to assess their income streams, verify tax codes, and begin meticulous record-keeping. The mid-year milestones of 31 July and 5 October serve as critical points for making advance tax payments and registering for Self Assessment, helping individuals manage cash flow and avoid missed deadlines. Finally, the 31 October and 31 January deadlines close the loop, marking the end of the return cycle and the settlement of any tax owed.
Staying ahead of these dates allows taxpayers to plan, avoid penalties, and engage with the tax system more confidently. Whether you are self-employed, have income outside of PAYE, or manage multiple sources of earnings, early preparation, accurate documentation, and awareness of each obligation throughout the year are key to maintaining financial control. By aligning your personal tax timeline with the official HMRC calendar, you can navigate the tax year with clarity and reduce the stress that often accompanies last-minute submissions.
Beyond compliance, treating tax management as a year-round priority can unlock strategic financial advantages. Timely filing and payments help build trust with HMRC, reduce the risk of audits, and make it easier to apply for mortgages, business loans, or other financial products where income verification is required. Moreover, keeping your records organised throughout the year gives you greater insight into your income patterns, deductible expenses, and savings opportunities. This can lead to more accurate forecasting, better decision-making, and even improved profitability if you run a business.
Ultimately, proactivity is the most valuable tool in a taxpayer’s toolkit. Those who approach tax season reactively often face stress, rushed decisions, and unexpected liabilities. By contrast, individuals who engage with their tax responsibilities consistently throughout the year position themselves for smoother filings, improved cash flow, and long-term financial resilience.