Are you self-employed, a landlord, a company director or earning extra income that isn’t taxed through PAYE? The Self Assessment 2025/26 tax year (running from 6 April 2025 to 5 April 2026) is now well underway, and the filing deadline is fast approaching.
At DBM Accountancy Ltd, we help hundreds of clients across the UK file accurate, stress-free Self Assessment tax returns every year. In this comprehensive guide, we break down everything you need to know for the 2025/26 Self Assessment: deadlines, tax rates and allowances, who must file, major changes (including Making Tax Digital), step-by-step filing tips, and how professional accountants can save you time, money and penalties.
Whether you’re searching for the Self Assessment 2025/26 deadline, income tax bands 2025/26, or “how to file my tax return without mistakes”, this article is designed to answer your questions and help you stay compliant with HMRC.
Why Self Assessment 2025/26 Matters This Year
The 2025/26 tax year is a pivotal one. With Making Tax Digital (MTD) for Income Tax rolling out from 6 April 2026, many sole traders and landlords will face new digital record-keeping rules during this tax year, even though they’ll still file their 2025/26 return the traditional way in early 2027.
Missing deadlines or underpaying tax can trigger automatic £100 penalties plus daily interest and further fines. Getting it right (or better still, letting experts handle it) protects your finances and peace of mind.
Key Deadlines for Self Assessment 2025/26
Mark these dates in your calendar now:
- 5 October 2026 – Deadline to register with HMRC for Self Assessment if you’re new to filing for the 2025/26 tax year.
- 31 October 2026 – Paper tax return deadline (not recommended, online is faster and gives you more time).
- 31 January 2027 – Online Self Assessment deadline and payment deadline for any tax owed.
- 30 December 2026 – Last date to file online if you want any tax owed added to your 2026/27 PAYE code (if eligible).
- 31 January 2027 – First payment on account due (if you paid tax last year).
- 31 July 2027 – Second payment on account due.
Pro tip from DBM Accountancy: File early! Submitting in December or early January avoids the last-minute HMRC website rush and gives you time to correct any issues.
Income Tax Rates & Allowances for 2025/26
The personal allowance and tax bands remain frozen for another year, which means more people are being pulled into higher tax bands due to inflation (known as fiscal drag).
England, Wales & Northern Ireland (2025/26):
| Tax Band | Taxable Income | Tax Rate |
|---|---|---|
| Personal Allowance | £0 – £12,570 | 0% |
| Basic rate | £12,571 – £50,270 | 20% |
| Higher rate | £50,271 – £125,140 | 40% |
| Additional rate | Over £125,140 | 45% |
- Personal Allowance: £12,570 (reduced by £1 for every £2 of income over £100,000, fully withdrawn at £125,140).
- Scotland has different bands (starter, basic, intermediate, higher, top rates). Contact us if you’re based north of the border.
- Other reliefs: Trading Allowance £1,000, Property Allowance £1,000, Personal Savings Allowance, Dividend Allowance (£500).
These frozen thresholds make accurate record-keeping more important than ever.
Who Needs to File a Self-Assessment Tax Return for 2025/26?
You must file if any of the following applied during the tax year:
- You were self-employed (sole trader) and earned more than £1,000 (before expenses).
- You are a partner in a business partnership.
- You received untaxed income (e.g. rental income over £1,000, foreign income, or dividends).
- You need to pay Capital Gains Tax.
- You have to pay the High Income Child Benefit Charge (income over £60,000).
- You earned over £100,000 (even if taxed through PAYE).
- You are a company director with dividends or other reportable income (new mandatory reporting rules apply from 2025/26).
Not sure? Use HMRC’s online checker or book a free 15-minute consultation with DBM Accountancy. We’ll tell you in minutes.
Major Changes Affecting Self Assessment 2025/26
1. Making Tax Digital (MTD) for Income Tax – Phase 1 Starts 6 April 2026. If your combined self-employment + property income exceeded £50,000 in the 2024/25 tax year, you must start using MTD compliant software from 6 April 2026. You’ll send quarterly updates to HMRC throughout 2025/26, but you still file your full 2025/26 Self Assessment return by 31 January 2027 in the usual way.
The lower thresholds are £30,000 (from April 2027) and £20,000 (from April 2028). DBM Accountancy offers MTD ready cloud software and full compliance support, so you don’t have to worry about quarterly deadlines.
2. Enhanced Director Reporting Company directors must now separately report dividends received from their close company, company name, registration number, and highest shareholding percentage.
3. Digital Platform Reporting Platforms like Uber, Deliveroo, Airbnb and Amazon already report seller income directly to HMRC, so more people are being automatically prompted to file.
How to File Your Self-Assessment Tax Return (Step-by-Step)
- Gather your records – P60s, P11Ds, bank statements, invoices, expense receipts, dividend vouchers, etc.
- Register or log in to your HMRC personal tax account (gov.uk).
- Use compatible software (especially if entering MTD).
- Complete all relevant sections – employment, self-employment, property, dividends, capital gains.
- Check and submit before 31 January 2027.
- Pay any tax due by the same date (bank transfer, debit card, or set up a payment plan).
Common mistakes we see: forgetting to claim allowable expenses, incorrect dividend allocation, missing MTD quarterly updates, or late registration.
Why Choose DBM Accountancy for Your 2025/26 Self Assessment?
- Fixed-fee Self Assessment service – no surprise bills.
- Cloud accounting & MTD compliant software included.
- 100% compliance guarantee – we handle HMRC queries.
- Tax-saving advice tailored to your situation (expense optimisation, pension contributions, etc.).
- London-based team supporting clients UK-wide via secure cloud systems.
Don’t risk penalties or overpaying tax. Let our chartered accountants take the stress out of Self Assessment.
Book your Self Assessment 2025/26 appointment today → www.dbmaccounts.co.uk/self-assessment Or call our friendly team on 02080165636 or 07547494789 or email [email protected].
Final Tips to Save Time & Tax in 2025/26
- Keep digital records from day one (especially if approaching MTD thresholds).
- Review your tax code now, claim any overpaid tax before 5 April 2026.
- Consider pension contributions or charitable donations before 5 April 2026 to reduce your tax bill.
- Subscribe to our newsletter for monthly tax tips and deadline reminders.
DBM Accountancy Limited – Your trusted partner for clear, compliant, and cost-effective Self Assessment services.
Last updated: March 2026. Always check the latest HMRC guidance or speak to a qualified accountant for personalised advice.