UK Small Business Tax Deadlines 2026/27
If you run a small business, sole trader setup, or limited company, missing a deadline isn't just annoying, it's expensive. HMRC's penalties start automatically, often from day one, whether or not you actually owe any tax.
We built this page to be the one you bookmark. No jargon, no sales pitch, just the dates that matter, kept current. Save it, share it with anyone running a business, and check back when you need it.
Last reviewed: July 2026. Deadlines can change, always double check anything time-sensitive with HMRC or your accountant before relying on it for a decision that matters.
The dates every small business owner should know
Self Assessment (sole traders, partners, company directors with other income)
- 5 October 2026 — register for Self Assessment if you started trading or had new untaxed income in 2025/26
- 31 October 2026 — paper tax return deadline for 2025/26
- 31 January 2027 — online tax return deadline for 2025/26, and payment of any tax owed
- 31 July 2027 — second payment on account, if you make payments on account
Miss the online filing deadline and it's an automatic £100 fine, even if you don't owe a penny. After three months, it's £10 a day on top.
Corporation Tax (limited companies)
Your dates depend on your company's year end, not a fixed date in the calendar. As a rule of thumb:
- Payment is due 9 months and 1 day after your accounting period ends
- Your CT600 return is due 12 months after your accounting period ends
So if your year end is 31 March, tax is due 1 January, and the return isn't due until 31 March the following year. Payment comes before filing, which catches people out.
Companies House
- Annual accounts: due 9 months after your financial year end (private limited companies)
- Confirmation statement: due once a year, within 14 days of your review period ending
Late accounts start at a £150 penalty and rise steeply the longer they're outstanding, so this one is worth calendaring separately from your Corporation Tax dates, even though they often land close together.
VAT (if you're VAT registered)
Returns and payment are due one month and seven days after the end of your VAT quarter.
Not sure which quarter you're on? It's on your VAT registration certificate.
Payroll, if you employ staff
- PAYE and NI: due by the 22nd of the following month if paying electronically (19th by post)
- P60s to employees: by 31 May
- P11Ds (benefits in kind): by 6 July
- Class 1A NI on P11D benefits: by 22 July
The big one for 2026: Making Tax Digital for Income Tax
If you're a sole trader or landlord with qualifying income over £50,000, MTD for Income Tax Self Assessment became mandatory from 6 April 2026. That means digital record keeping and quarterly updates to HMRC using compatible software, replacing the old once-a-year Self Assessment approach.
The threshold drops to £30,000 from April 2027, and £20,000 from April 2028, so this will catch most small business owners eventually. If you're anywhere near £50,000 in qualifying income now, it's worth getting ahead of this rather than waiting for it to become urgent.
Not sure which of these applies to you?
That's normal, most people are dealing with two or three of these at once, not all of them, and first-year businesses often have dates that don't follow the standard pattern. If you'd rather just have someone tell you what's due and when, get in touch and we'll map it out for you.