How Soon Should I Submit My 2024/25 Self-Assessment Tax Return?

If you earn income outside of PAYE (Pay As You Earn), you may need to complete a Self-Assessment Tax Return in the UK. This applies to self-employed individuals, sole traders, landlords, company directors, and those with additional income streams. HMRC uses this system to calculate how much tax you owe based on your earnings and expenses.

Filing your Self-Assessment Tax Return on time is crucial. Missing the deadline can lead to automatic fines, interest charges on late payments, and unnecessary stress. The quicker you submit your return, the more time you have to plan your tax payments and correct any mistakes.

So, how soon should you submit your Self-Assessment Tax Return? The simple answer: the sooner, the better! Filing early helps you stay in control, reduces last-minute pressure, and increases your chances of receiving any tax refunds sooner. In this guide, we’ll break down the 2024/25 self-assessment tax return deadlines, the benefits of early filing, and how to make the process easier.

The tax year runs from April 6th to April 5th of the following year. The relevant 2024/25 tax year dates are April 6th, 2024, to April 5th, 2025.

HMRC has set deadlines for registration, paper and online submissions, and tax payments. Missing these dates can lead to penalties, so it’s best to stay ahead of the schedule.

Self Assessment Registration Deadline – Who Needs to Register and By When?

If you are filing a Self-Assessment Tax Return for the first time, you should register for Self Assessment. This applies to:

• Self-employed individuals earning more than £1,000 in a tax year.
• Company directors who receive income outside of PAYE.
• Landlords earning rental income.
• Those receiving untaxed income, such as dividends, foreign income, or side earnings.

Registration Deadline - 5th October 2025

If you are new to Self-Assessment, you must register by 5th October 2025 for the 2024/25 tax year. Once registered, HMRC will provide you with a Unique Taxpayer Reference (UTR) and instructions on how to file your return.

Self Assessment Tax Filing and Payment Deadlines

The deadlines for your self-assessment tax return for the 2024/25 tax year are as follows:

Paper Tax Return Deadline - 31st October 2025

if you prefer to submit your tax return by post, you must submit your Self Assessment tax return by Midnight, 31st October 2025. Paper submissions take longer to process and thus, HMRC encourages online filing.

Online Tax Return Deadline – 31st January 2026

if you submit online, you must submit your tax return by Midnight, 31st January 2026.

Watch below video from HMRC to find out more about completing your first tax return:

Payments on Account

When completing your self-assessment tax return, it's essential to consider "payments on account." This system allows you to make advance payments toward your tax bill for the following year. Here's what you need to know:

1. First Payment on Account: If your tax bill exceeds £1,000, you must make an initial payment on account by January 31st, 2026, along with any outstanding tax from the previous tax year.
2. Second Payment on Account: The second payment is due by July 31st, 2026, and represents another advance payment toward your 2024/25 tax year tax bill.

Before completing your self-assessment tax return, you must gather several key pieces of information. These include:

1. Income Information: Ensure you have accurate records of all your income sources, including invoices, bank statements, and receipts.
2. Expenses Documentation: Keep track of your business expenses, such as receipts for office supplies, travel expenses, and equipment purchases. This information will help you claim allowable deductions and reduce your taxable income.
3. Updating Accounting Software: If you use accounting software like FreeAgent, update it with all your financial transactions and ensure that your data is accurate and current.
4. P60: If you are employed and receive income through PAYE, you will need your P60 form, which provides details of your salary and taxes paid during the tax year.

Once you have gathered all the necessary information and completed your self-assessment tax return, reviewing it carefully for accuracy is essential. Double-check your income, expenses, and any claimed deductions. After finalising your return, your accountant can help you calculate your tax liability.

Payments for the 2024/25 tax year, including any outstanding tax from the previous tax year and payments on account, are due by January 31st, 2026.

Please complete the deadlines for filing your self-assessment tax return to avoid the penalties HMRC imposes. The penalties vary depending on the delay:

From the 1st February to 30th April (over 1 day late) - £100 fine

From the 1st May to 31st July (over 3 months late) - £10 a day fine up to a maximum of £900 (90 days) for every day it is late

From the 1st August to 31st January (over 6 months late) - £300 fine or 5% of the tax owing, which ever is greater

From the 1st February of the following year (over 12 months late) - another £300 fine or 5% of the tax owing, which ever is greater.

Filing your Self-Assessment Tax Return early comes with several benefits. Many people wait until the deadline, which can lead to last-minute stress, mistakes, and even penalties. Submitting your return ahead of time gives you more control over your finances and allows you to deal with any issues before they become problems.

1. Faster Tax Refunds

If HMRC owes you a tax refund, filing early means you’ll get your money back sooner. Refunds are typically processed faster outside of peak filing season, so the earlier you submit, the quicker you’ll receive any overpaid tax.

Many people overpay tax due to incorrect PAYE codes, work-related expenses, or tax relief on pensions. Submitting your return early helps speed up the refund process, giving you access to your money when you need it.

2. Avoiding Last-Minute Stress

Leaving your tax return until the last minute can create unnecessary pressure. Filing early gives you more time to:

• Collect all required documents, such as income statements and expense receipts.
• Double-check your figures to reduce the risk of errors.
• Get help from an accountant if needed, without rushing.

Submitting early also means avoiding delays caused by high demand on HMRC’s online system, which tends to slow down as the deadline approaches.

3. Avoid Penalties

Missing the Self-Assessment Tax Return deadline results in automatic fines. Even if you are just one day late, HMRC will charge a £100 penalty. The longer you delay, the higher the penalties.Late payments also attract interest, increasing the amount you owe. Filing early removes the risk of missing deadlines and facing unnecessary fines.

4. Better Financial Planning

Filing your tax return early helps you understand how much tax you owe well in advance. This gives you more time to:

• Plan for your tax payment and avoid cash flow issues.
• Budget for any upcoming expenses.
• Spread out payments if your tax bill is higher than expected.

For those making payments on account, knowing your tax liability early can help you prepare for upcoming instalments.

5. Potential for Lower Accountant Fees During Non-Peak Times

‍Accountants for self-employed are often busier — and may charge higher fees — as the submission deadline approaches. By filing early, you can work with them during quieter periods, potentially saving money and getting more personalised support.

Filing a Self-Assessment Tax Return may be straightforward for some, but there are situations where professional help can make a big difference. An accountant for sole trader not only saves you time but can also help you avoid penalties and identify tax-saving opportunities.

Signs You Need Professional Help

Consider hiring an accountant if:

• Your income comes from multiple sources: If you have various income streams, such as rental properties, freelance work, or dividends, an  can help you report everything correctly.
• You’re self-employed or own a business: Managing business expenses, tax deductions, and VAT can be complicated. Professional guidance simplifies the process.
• You’ve experienced a significant financial change: Events like selling assets, inheriting money, or starting a new business can impact your tax obligations.
• You’ve received a tax investigation letter: An accountant can help respond to HMRC queries and reduce your stress during audit.
• You want to save time: If you prefer to focus on your business or personal life rather than tax paperwork, outsourcing to an accountant is a smart choice.

How GoForma Can Help Streamline the Process

‍GoForma offers expert accounting services tailored to your specific needs. Our team handles everything from gathering the right documents to completing and submitting your tax return. By choosing GoForma, you’ll have peace of mind knowing that your taxes are in good hands.

As a GoForma client, you also get access to FreeAgent accounting software at no additional cost with all packages. This powerful tool helps track expenses, generate invoices, and manage your finances seamlessly. It makes staying on top of your accounts easy, whether you're self-employed or running a small business.

Working with GoForma gives you the best of both - expert support from experienced accountants and free access to cutting-edge accounting software.

If you're looking to sort out your tax return without long-term commitments, why not try our Self Assessment Tax Return service? You'll get expert help, accurate filing, and a stress-free experience — all without tying yourself to an ongoing plan. Book a free consultation today and tick your tax return off your to-do list!