UK tax deadlines for the self-employed: your 2026 and 2027 calendar

Self-employment gives you flexibility over your working hours. It gives you no flexibility at all over HMRC's deadlines. Miss one and the penalty is automatic — £100 minimum for a late self-assessment return, even if your tax bill comes to zero.

This guide sets out every key tax date that self-employed tradespeople need to know for 2026 and 2027, including self-assessment filing, payment on account dates, VAT deadlines, and the new Making Tax Digital milestones.

The UK tax year

The UK tax year runs from 6 April to 5 April the following year. So the 2025/26 tax year covers income earned between 6 April 2025 and 5 April 2026. It is an odd set of dates with roots in calendar changes back in 1752, but it is not going to change anytime soon.

Self-assessment deadlines

For the 2025/26 tax year (income earned 6 April 2025 to 5 April 2026)

• 5 October 2026: Register for self-assessment if you are newly self-employed and have not yet told HMRC. Failing to register on time can result in a penalty.
• 31 October 2026: Deadline for filing a paper tax return (almost nobody does this anymore).
• 31 January 2027: Deadline for filing your online self-assessment return AND paying any tax owed for 2025/26, plus the first payment on account for 2026/27.
• 31 July 2027: Deadline for the second payment on account for 2026/27.

For the 2024/25 tax year (if you are catching up)

• Online filing deadline: 31 January 2026 (past)
• Second payment on account: 31 July 2026

What are payments on account?

If your self-assessment tax bill is more than £1,000 and less than 80% of your income is taxed at source (like PAYE), HMRC requires you to make advance payments towards next year's bill. These are called payments on account.

Each payment on account is half of your previous year's tax bill. So if you owed £4,000 for 2025/26, HMRC expects you to pay £2,000 on 31 January 2027 and another £2,000 on 31 July 2027 — before you even know what your 2026/27 bill will be.

If you think your actual 2026/27 bill will be lower (perhaps because you had a slower year), you can apply to reduce your payments on account. You do this through your HMRC online account or by completing form SA303. If you reduce too much and the actual bill is higher, interest is charged on the shortfall.

Penalties for missing deadlines

Late filing penalties

• 1 day late: £100 automatic penalty
• 3 months late: £10 per day, up to £900
• 6 months late: 5% of the tax due, or £300 — whichever is higher
• 12 months late: a further 5% or £300

Late payment penalties

• 30 days late: 5% of the tax owed
• 6 months late: a further 5%
• 12 months late: a further 5%
• Interest accrues daily on unpaid tax

VAT deadlines

If you are VAT-registered, your VAT return and payment are due one calendar month and seven days after the end of each VAT quarter. Your quarter end dates depend on your VAT registration stagger group:

• Stagger 1: March, June, September, December — returns due 7 May, 7 August, 7 November, 7 February
• Stagger 2: January, April, July, October — returns due 7 March, 7 June, 7 September, 7 December
• Stagger 3: February, May, August, November — returns due 7 April, 7 July, 7 October, 7 January

CIS deadline

If you are a CIS contractor (deducting CIS tax from subcontractors), your monthly CIS return is due by the 19th of the following month. So April's return is due 19 May. Payments to HMRC for CIS deductions are due by the 22nd of the month (or 19th if paying by post). Late CIS returns attract penalties starting at £100.

Making Tax Digital milestones

This is the big new deadline many tradespeople are not yet aware of:

• 6 April 2026: MTD for Income Tax applies to self-employed people and landlords with income over £50,000. You must keep digital records and submit quarterly updates to HMRC, in addition to your annual return.
• 6 April 2027: MTD for Income Tax extends to those with income over £30,000.
• 6 April 2028: MTD extends to those with income over £20,000.

If you are affected from April 2026, you will need MTD-compatible software to send quarterly summaries to HMRC. The annual return is not abolished — it becomes a final declaration that confirms the quarterly figures. Our guide on Making Tax Digital for sole traders in 2026 explains what you need to do to get ready.

Other key dates to know

• 6 April 2026: New tax year begins. New personal allowance thresholds apply. Check the current income tax rates on GOV.UK.
• 31 March 2026: End of the 2025/26 corporation tax year (not relevant to sole traders, but relevant if you trade through a limited company).

Useful tools

Our self-assessment tax calculator lets you estimate your bill ahead of the January deadline. Our VAT calculator helps you check your quarterly VAT figures before submitting.

Summary

The two dates you absolutely must not miss are 31 January (file your return and pay tax owed) and 31 July (second payment on account). VAT-registered businesses have quarterly deadlines on top of these. From April 2026, if you earn over £50,000, you also have quarterly MTD submissions to factor in. Put all these dates in your calendar now — HMRC gives no credit for forgetting.