10 Tax Deadlines Every UK Sole Trader Must Know in 2026/27
Why Missing a Deadline Costs More Than You Think
Miss your Self Assessment deadline by a single day and you're looking at an automatic £100 penalty — even if you owe nothing. Leave it three months and daily penalties stack up at £10 per day.
With Making Tax Digital rolling out quarterly submissions, there are more deadlines than ever. The MTD penalties regime uses a points-based system — miss enough and you'll face a £200 fine.
The simplest way to avoid this? Know the dates in advance. Here's every deadline that matters for the 2026/27 tax year.
1. 5 April 2027: Tax Year End
What it is: The 2026/27 tax year runs from 6 April 2026 to 5 April 2027. This is the cut-off for all income and expenses on your 2026/27 return.
What you should do: Review your records in the weeks before. Make sure expenses are recorded, receipts captured, and books up to date. Run through our year-end tax checklist to catch any missed deductions. If you've kept proper digital records, this should be straightforward.
2. 6 April 2027: MTD Quarterly Period 1 Starts
What it is: For sole traders within the MTD threshold, Q1 begins. Make sure your HMRC-compatible software is connected. If you've just crossed the threshold, sign up for MTD before this date.
MTD quarterly periods:
- Q1: 6 April – 5 July
- Q2: 6 July – 5 October
- Q3: 6 October – 5 January
- Q4: 6 January – 5 April
3. 31 May 2027: P60 Deadline
What it is: If you employ anyone (yes, some sole traders do have employees), you must provide them with a P60 by 31 May. The P60 summarises their pay and tax deductions for the tax year.
What you should do: If this applies to you, ensure your payroll is finalised and P60s are issued. If you don't have employees, you can safely ignore this one.
4. 5 July 2027: MTD Q1 Submission Deadline
What it is: Your first quarterly update to HMRC is due, covering 6 April to 5 July 2027.
What you should do: Review transactions, confirm categorisation, and submit through your MTD software. This is a summary, not polished accounts. Under the penalty points system, each missed submission earns a point — accumulate enough and you face a £200 fine.
5. 31 July 2027: Second Payment on Account
What it is: If your previous Self Assessment bill was over £1,000, HMRC requires payments on account — advance payments split into two instalments (31 January and 31 July).
What you should do: This is 50% of last year's tax bill. If you've been following the 30% rule, the money should already be set aside. If your income has dropped, you can apply to reduce payments on account through your HMRC online account.
6. 5 October 2027: Register as Self-Employed
What it is: If you started self-employment between 6 April 2026 and 5 April 2027, you must register with HMRC by this date.
What you should do: Register online. Your UTR number arrives by post and can take 2-3 weeks, so don't leave it late.
7. 5 October 2027: MTD Q2 Submission Deadline
What it is: Your second quarterly update to HMRC, covering the period 6 July to 5 October 2027.
What you should do: Same as Q1 — review, categorise, submit. By now, you should be settling into a rhythm with your quarterly submissions. If you're using software that connects to your bank, most of the work should already be done.
8. 5 January 2028: MTD Q3 Submission Deadline
What it is: Third quarterly update, covering 6 October 2027 to 5 January 2028.
What you should do: Submit your Q3 update. This is also a good time to start thinking about your full-year tax position, since you'll have nine months of data. Check whether your tax bill estimate looks right and whether you need to adjust your plans.
9. 31 January 2028: Self Assessment Deadline + First Payment on Account
What it is: This is the big one. Three things converge on 31 January:
- Self Assessment tax return for 2026/27 must be filed online.
- Balancing payment — any remaining tax owed for 2026/27 (after subtracting your payments on account) is due.
- First payment on account for 2027/28 — 50% of your 2026/27 tax bill, paid in advance towards next year.
What you should do: Don't wait until January. You can file as early as 6 April 2027. Clean digital records mean your return takes a couple of hours. This is the deadline most people miss — don't be one of them.
10. 5 April 2028: MTD Q4 Submission Deadline
What it is: Your final quarterly update for the 2026/27 year, covering 6 January to 5 April 2028. (Note: MTD quarterly periods may span across tax years, so your Q4 for 2026/27 extends into the start of the 2027/28 year.)
What you should do: Submit your final quarterly update. After this, HMRC will have a complete picture of your income and expenses for the year, aligned with what you reported on your Self Assessment.
How to Actually Remember All of This
Ten deadlines across twelve months is manageable — until real life gets in the way. Here are three approaches:
Option 1: Calendar Reminders
Add every deadline to your phone calendar with two reminders: one a week before, one three days before. It takes ten minutes to set up and costs nothing.
Option 2: A Spreadsheet
Create a simple tax deadlines tracker with each deadline, what's required, and a checkbox for completion. Pin it to your desk or bookmark it in your browser.
Option 3: Let Software Handle It
Accounted's smart deadlines feature tracks every HMRC deadline relevant to your situation — based on your registration status, VAT position, and MTD obligations.
You get notifications in advance with clear instructions. If your records need attention, Penny — our AI bookkeeper — flags it early enough to fix. Because the best deadline strategy is building a system where the work is done before the deadline arrives.
Ready to simplify your bookkeeping? Try Accounted free for 14 days →
Related Reading
Related reading: When to Outsource as a Small Business Owner.
For step-by-step guidance, see our article on How to Handle Business Debt as a Sole Trader.
For step-by-step guidance, see our article on How to Close Your Sole Trader Business Properly.
Related reading: Working with a Virtual Assistant as a Sole Trader.
For step-by-step guidance, see our article on How to Fire a Client Professionally.
Related reading: Year-End Accounts Preparation: Complete Checklist.
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