When Should I Submit My Self Assessment Tax Return?
When Should I Submit My Self Assessment Tax Return?
You can submit your 2025/26 Self Assessment tax return from 6 April 2026. The normal online filing deadline is 31 January 2027 — but you don't have to wait until January to file.
You can submit your 2025/26 return once the tax year has ended and your records are ready.
The normal deadline for submitting a paper Self Assessment tax return.
The normal deadline to file online and pay your balancing Self Assessment tax bill.
Good to know: Filing your Self Assessment early does not normally mean paying early. Your balancing payment for 2025/26 is generally due by 31 January 2027.
When Should I Submit My Self Assessment Tax Return?
If you need to complete a UK Self Assessment tax return, you do not have to wait until January. Your return can normally be submitted as soon as the relevant tax year has ended and you have the information needed to complete it accurately.
For the 2025/26 tax year, you can submit your Self Assessment tax return from 6 April 2026. The normal online filing deadline is 31 January 2027.
There is usually little benefit in deliberately waiting until January. Once you have complete and reliable figures, filing earlier can tell you exactly what tax you owe and gives you considerably more time to budget. Filing early does not normally mean that you have to pay your tax early.
The 2025/26 tax year ends on 5 April 2026, so a return can normally be submitted from the following day.
Submit once your income, expenses, tax documents and other relevant figures are complete rather than automatically waiting until January.
This is normally the final date for submitting the 2025/26 return online and paying the balancing tax due.
Self Assessment Deadlines for the 2025/26 Tax Year
The tax year runs from 6 April 2025 to 5 April 2026. These are the main dates to have in your diary.
| What you need to do | 2025/26 deadline | What it means |
|---|---|---|
| Tax year ends | 5 April 2026 | The 2025/26 tax year is complete. |
| Earliest normal filing date | 6 April 2026 | You can start submitting your 2025/26 return. |
| Register for Self Assessment if required | 5 October 2026 | Important for many people who need to file for the first time or need to reactivate Self Assessment. |
| Paper tax return deadline | 31 October 2026 | Normal deadline if you are submitting a paper return. |
| Online return if eligible tax is to be collected through PAYE | 30 December 2026 | Relevant where you meet HMRC's conditions for collecting a Self Assessment underpayment through your PAYE tax code. |
| Online Self Assessment deadline | 31 January 2027 | Normal final deadline for filing the 2025/26 return online. |
| Balancing tax payment | 31 January 2027 | Normal payment deadline for tax still due for 2025/26, together with any first payment on account that applies. |
| Second payment on account | 31 July 2027 | The second payment on account towards 2026/27, where payments on account apply. |
So, What Is the Best Time to Submit a Self Assessment?
For most people, the practical answer is: submit your return once you have all the information needed to prepare it accurately.
There is no requirement to wait until the January deadline. If your records are complete in May, June, September or October, your return can normally be prepared and filed then.
This is particularly useful if you are self-employed, a landlord, receive dividends or investment income, have capital gains, or have several different sources of taxable income.
You know your tax bill earlier
Filing establishes your actual Self Assessment liability rather than leaving you to estimate what may be due in January.
You have longer to budget
Knowing the amount several months before the payment deadline can make cash-flow planning considerably easier.
You reduce deadline pressure
You have more time to locate missing information and deal with questions before the January rush.
You can identify repayments sooner
If your completed return shows that you have overpaid tax, an earlier submission means the repayment process can begin sooner.
Should I Submit My Tax Return Straight After 6 April?
You can, but only if you have sufficient information to prepare an accurate return.
Filing on 6 April simply to get the return out of the way is not always sensible if you are still waiting for important information. Depending on your circumstances, this might include:
| Information you may need | Examples |
|---|---|
| Employment information | P60, P45 and P11D information where applicable |
| Self-employment records | Sales, expenses, bank transactions and accounting records |
| Property records | Rental income, allowable costs and property finance information |
| Savings and investments | Interest statements and dividend information |
| Capital gains information | Purchase costs, disposal proceeds and relevant allowable costs |
| Pension information | Relevant pension contributions and pension income |
| Other taxable income | Foreign income and other income that needs reporting |
The objective should therefore be to file as early as reasonably practical, but not before the information needed for an accurate return is available.
If I Submit My Tax Return Early, Do I Have to Pay Early?
No — not normally. Filing and paying are separate Self Assessment obligations.
For the 2025/26 tax year, the normal balancing payment deadline is 31 January 2027. You can therefore submit your return well before January without having to make the balancing payment at the same time.
Some taxpayers prefer to make voluntary payments before the deadline, but filing the return early does not in itself normally require early payment.
Why Can 30 December Be an Important Self Assessment Date?
If you owe less than £3,000 and already pay tax through PAYE, HMRC may be able to collect your Self Assessment bill through your wages or pension by adjusting your tax code.
To be considered for this, an online return normally needs to be submitted by 30 December, and HMRC's other eligibility conditions must also be satisfied.
What About Payments on Account?
Filing early can also help you understand whether payments on account will increase the amount you need to pay in January.
Payments on account are advance payments towards a future Self Assessment bill. Where they apply, each payment is normally based on half of the relevant previous year's tax liability.
The first payment is normally due on 31 January and the second on 31 July.
Example: Filing Early Versus Waiting Until January
5 April 2026
The 2025/26 tax year ends.
June 2026
Sarah, a self-employed consultant, has completed her bookkeeping and received the information needed for her return.
July 2026
Her 2025/26 Self Assessment is prepared and submitted. She now knows the amount due in January.
31 January 2027
Sarah pays the balancing payment and any first payment on account due. Filing in July did not require her to make the normal January payment six months early.
Do I Need to Submit a Self Assessment Tax Return?
Not everyone needs to file a Self Assessment return. Whether you need one depends on your individual circumstances and the income or gains you received during the tax year.
Common situations that can result in a filing requirement include self-employment, partnership income, property income, certain foreign income, capital gains and other income that has not been fully taxed elsewhere.
If HMRC has issued you with a notice requiring a tax return, you should not simply ignore it because you believe no tax is due. If you think a return is no longer required, the appropriate step is to contact HMRC and ask whether the filing requirement can be withdrawn.
What Happens If I Submit My Self Assessment Late?
Missing the filing deadline can result in penalties even where little or no tax is ultimately payable.
| How late? | Potential late-filing penalty |
|---|---|
| Immediately after the filing deadline | Initial £100 late-filing penalty |
| More than 3 months late | £10 per day for up to 90 days |
| 6 months late | Further penalty of £300 or 5% of the tax due, whichever is greater |
| 12 months late | A further penalty applies and can be higher in certain circumstances. |
Separate penalties and interest can also apply where the tax itself is paid late.
Does Making Tax Digital Change the Self Assessment Deadline?
Making Tax Digital for Income Tax is now being introduced in stages for qualifying sole traders and landlords.
From 6 April 2026, it applies to qualifying individuals whose gross self-employment and property income exceeded £50,000 in 2024/25. The threshold falls to more than £30,000 from 6 April 2027 and more than £20,000 from 6 April 2028.
MTD introduces digital record keeping and quarterly updates for people within its scope, but the annual tax return and tax payment deadline remains 31 January following the relevant tax year.
Our View: Don't Treat 31 January as Your Target Filing Date
The 31 January deadline is the latest normal online filing date, not necessarily the best date to submit your return.
In practice, we recommend preparing a Self Assessment return once the relevant records are complete. This gives time to identify missing information, review allowable deductions, calculate the liability and plan for the payment before the deadline arrives.
Filing early is particularly valuable where payments on account may apply because the January cash requirement can be higher than the taxpayer initially expects.
Self Assessment Filing Date FAQs
When should I submit my Self Assessment tax return?
You can normally submit it from 6 April following the end of the relevant tax year. Rather than waiting until January, a sensible approach is to submit once you have complete and reliable information. The normal online deadline for the 2025/26 return is 31 January 2027.
What is the earliest date I can submit my 2025/26 tax return?
The 2025/26 tax year ends on 5 April 2026, so the return can normally be submitted from 6 April 2026.
What is the Self Assessment deadline for 2025/26?
The normal deadline for filing the 2025/26 Self Assessment return online is 31 January 2027. The normal paper filing deadline is 31 October 2026.
Do I have to wait until January to submit my tax return?
No. January is the normal final online filing deadline. You can submit much earlier once the tax year has ended and you have the information needed to prepare an accurate return.
If I submit my tax return early, do I have to pay immediately?
Normally, no. For the 2025/26 tax year, the balancing payment is normally due by 31 January 2027 even if the return was submitted several months earlier.
Can I submit my Self Assessment on 6 April?
Potentially yes, because the previous tax year has ended. However, you should make sure you have all the information needed to prepare the return accurately rather than filing prematurely.
Why should I file my Self Assessment early?
Filing earlier establishes how much tax you owe, gives you longer to budget, reduces last-minute deadline pressure and provides more time to resolve missing information or questions.
When do I need to register for Self Assessment?
If you need to complete a return for 2025/26 and are required to register or reactivate Self Assessment, the normal notification deadline is 5 October 2026.
Can I pay my Self Assessment through my PAYE tax code?
In some circumstances. If you owe less than £3,000, already pay tax through PAYE and meet HMRC's other conditions, HMRC may be able to collect the amount through your tax code. An online return normally needs to be submitted by 30 December for this option.
Can I change my Self Assessment after submitting it?
Yes. A Self Assessment return can normally be amended within 12 months of the filing deadline. This means you do not necessarily have to delay filing simply because you are worried that a genuine error could never be corrected.
Need Help Filing Your Self Assessment?
The Online Accountants provide a fixed-price online Self Assessment service for individuals, sole traders, landlords, directors and people with multiple sources of income. We prepare your return, calculate the tax due and submit it directly to HMRC after your approval.
View Our Self Assessment Filing ServiceLast reviewed: September 2026. Tax rules and HMRC procedures can change. This guide provides general information and does not constitute personalised tax advice.