The 2025/26 tax year ended on 5 April 2026, which means anyone who needs to complete a Self Assessment tax return can now prepare and submit it. Although the main online deadline is still several months away, September is a good time to get organised—especially as the deadline to notify HMRC that you need to file is approaching.
This year also brings an important change. Making Tax Digital for Income Tax is now live for the first group of sole traders and landlords, while the next group needs to prepare for April 2027.
Do you need to submit a 2025/26 tax return?
You will normally need to submit a Self Assessment tax return if, during the tax year from 6 April 2025 to 5 April 2026, you:
- were self-employed as a sole trader and had more than £1,000 of gross trading income before expenses;
- were a partner in a business partnership;
- had Capital Gains Tax to pay after selling or disposing of an asset;
- had to pay the High Income Child Benefit Charge and it was not collected through PAYE; or
- received untaxed income from sources such as property, tips, commission, savings, dividends or overseas income.
Not every person with additional income will automatically need to file, as allowances and individual circumstances can affect the position. If you are unsure, it is better to check early instead of discovering the requirement after a deadline has passed.
The key Self Assessment deadlines
For the 2025/26 tax year, the main dates are:
| Date | What is due |
|---|---|
| 5 October 2026 | Tell HMRC if you need to complete a return and you have not filed before, or you did not need to file for 2024/25. |
| 31 October 2026 | Deadline for HMRC to receive a paper tax return. |
| 30 December 2026 | Submit online by this date if you want HMRC to consider collecting eligible tax through your PAYE tax code. |
| 31 January 2027 | Deadline for the online 2025/26 tax return and payment of the tax due. This may include a first payment on account for 2026/27. |
| 31 July 2027 | Second payment on account for 2026/27, where applicable. |
If you register after 5 October, HMRC may give you a separate three-month filing deadline. However, the tax you owe is still normally due by 31 January 2027, so late registration should not be treated as extra time to pay.
Making Tax Digital for Income Tax: what has changed?
Making Tax Digital for Income Tax began on 6 April 2026 for sole traders and landlords whose qualifying income was more than £50,000 on their 2024/25 tax return.
Qualifying income means the combined gross turnover from self-employment and property before expenses. Employment income, dividends, pensions and an individual partner’s share of partnership profit do not normally count towards this threshold.
If the rules apply, you need to:
- keep digital records of relevant business or property income and expenses;
- use software that is compatible with Making Tax Digital;
- submit quarterly summaries to HMRC; and
- complete and submit your annual tax return through compatible software.
The first quarterly update for the 2026/27 tax year was due by 7 August 2026 and the second is due by 7 November 2026 for taxpayers using the standard update periods. HMRC has confirmed that it will not apply penalty points for late quarterly updates during 2026/27, but the updates still need to be submitted before the annual tax return can be completed.
The rollout will continue in stages:
| Qualifying income shown on | Income threshold | MTD start date |
|---|---|---|
| 2024/25 tax return | More than £50,000 | 6 April 2026 |
| 2025/26 tax return | More than £30,000 | 6 April 2027 |
| 2026/27 tax return | More than £20,000 | 6 April 2028 |
This makes the 2025/26 return particularly important. If your qualifying income is more than £30,000, the figures reported on that return may bring you into Making Tax Digital from 6 April 2027. Preparing now gives you time to choose suitable software and improve your bookkeeping process before the new tax year begins.
What should you gather now?
Starting early is usually much easier than trying to reconstruct a year of activity in January. Depending on your circumstances, you may need:
- your Unique Taxpayer Reference and National Insurance number;
- sales records, invoices and platform or payment-provider statements;
- business bank and credit-card statements;
- receipts and details of allowable business expenses;
- P60, P45 or other employment income information;
- CIS deduction statements, if you work under the Construction Industry Scheme;
- rental income and property expense records;
- bank interest, dividend and pension statements;
- pension contribution and Gift Aid details;
- student or postgraduate loan information; and
- records of assets sold during the year.
Good records do more than support the return. They help identify allowable expenses, reduce errors and give you a clearer view of the amount you may need to pay.
Why filing early can help
Submitting before January does not normally mean paying tax early. It means you can find out what you owe sooner and plan your cash flow properly.
This is particularly useful if payments on account apply. Your January payment could include both the balance for 2025/26 and the first payment towards 2026/27, which can make the amount higher than expected.
Late filing and late payment can also lead to penalties and interest. Under the standard Self Assessment regime, a late return normally attracts an initial £100 penalty, with further penalties if the delay continues. Taxpayers within Making Tax Digital are moving to a points-based system for late submissions, so the rules applying to you may depend on whether you are already required to use the new service.
How LAbooks Limited can help
At LAbooks Limited, we help sole traders, landlords and small-business owners turn their records into an accurate, complete Self Assessment tax return. We can support you with bookkeeping clean-up, reviewing income and expenses, calculating the tax position and submitting the return to HMRC.
We can also help you understand whether Making Tax Digital applies to you and prepare your bookkeeping systems for the next stage of the rollout.
The earlier we receive your records, the more time there is to resolve missing information, check the figures and help you plan for the tax payment. If your 2025/26 return is still on your to-do list, now is a good time to start.
Need help with your Self Assessment tax return? Contact LAbooks Limited to discuss your records and filing requirements.
This article provides general information based on HMRC guidance available on 16 September 2026. Tax treatment depends on individual circumstances and rules may change. Please seek advice specific to your situation.