The UK small business tax calendar (every deadline, plain English)

Note: Dates and thresholds in this guide are general and change. Always confirm the current deadlines for your business with HMRC and Companies House — your exact dates depend on your year-end and registration dates.

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The whole tax year, on one page

If you've ever lain awake wondering whether you've missed something with HMRC, this page is for you. Running a small business in the UK means juggling a handful of deadlines from different places — HMRC for tax, Companies House for company filings — and nobody hands you a single calendar that lists them all.

So here it is. One plain-English list of the deadlines that actually apply to small UK businesses, what each one is, and roughly when it lands. Bookmark it. We'll keep it updated each year, because these dates and the figures around them shift.

A quick word before we start: not every deadline here applies to you. A sole trader doesn't file company accounts. A business that isn't VAT-registered ignores the VAT dates entirely. Read the ones that match your setup and skip the rest.

The UK tax year (so the dates make sense)

The UK personal tax year is a slightly odd thing: it runs from 6 April to 5 April the following year, not January to December. That quirk is centuries old and we're stuck with it. So when you see "the 2025/26 tax year," that means 6 April 2025 to 5 April 2026.

Companies are different. A limited company has its own accounting year (your "year-end"), set when you incorporated — often the end of the month you registered in. That's why two founders can have completely different Corporation Tax deadlines: they're counting from different year-ends.

Keep that split in your head — personal tax year (fixed) versus company year (yours) — and the rest of this calendar stops feeling random.

Self Assessment (if you're a sole trader, in a partnership, or take dividends)

Self Assessment is how HMRC collects tax that isn't taken automatically through payroll. If you're a sole trader, a partner, or a company director taking dividends, you'll likely file one.

Register by 5 October. If this is your first year needing to file, you must tell HMRC by 5 October after the end of the tax year you started earning. Miss this and you can face penalties even before you've filed anything.

Paper return deadline: 31 October. Almost nobody files on paper anymore, but if you do, it's due months earlier.

Online return and payment: 31 January. This is the big one. By midnight on 31 January you must file your online return and pay the tax owed for the previous tax year. So the 2024/25 return (year ending 5 April 2025) is due 31 January 2026.

Payments on account: 31 January and 31 July. Here's the bit that surprises people. HMRC often asks you to pay next year's tax in two instalments up front — half on 31 January, half on 31 July. The first time this hits, your January bill can feel brutal, because you're paying last year's tax and the first instalment of this year's at once. It's not a mistake. (See: Self Assessment for the terrified.)

VAT (only if you're VAT-registered)

You only deal with VAT deadlines once you're registered — which is compulsory once your taxable turnover crosses the VAT threshold (confirm the current figure with HMRC, as it changes), or optional before that.

Most businesses file quarterly. Your quarters depend on the dates HMRC gave you, so there's no single national date — check your VAT account. The rule of thumb, though, is consistent:

One month and seven days after the quarter ends. That's your deadline to both file the VAT return and pay what you owe. So a quarter ending 31 March is typically due by 7 May. Set the reminder for the 7th and you'll never be late.

Almost all VAT-registered businesses must now file through Making Tax Digital — using compatible software that keeps digital records, not a paper form. (See: What is Making Tax Digital and does it affect me?)

Corporation Tax (limited companies only)

This one trips founders up because the payment deadline comes before the filing deadline — the opposite of personal tax.

Pay your Corporation Tax: 9 months and 1 day after your year-end. If your company year ends 31 March, the tax is due by 1 January. You pay first.

File your Company Tax Return (CT600): within 12 months of your year-end. You get three extra months to file the actual return after you've paid.

Yes, that's odd: pay at nine months, file at twelve. Budget for the payment date, not the filing date. (See: What is Corporation Tax and when do I pay it?)

PAYE and RTI (if you run payroll, including paying yourself a salary)

The moment you put anyone on a payroll — even just yourself as a director on a small salary — PAYE deadlines apply.

Report on or before payday (RTI). Every time you run payroll, you must send HMRC a report (called a Full Payment Submission) on or before the day you pay people. This is "Real Time Information" — it's continuous, not annual.

Pay HMRC by the 22nd. The PAYE tax and National Insurance you've deducted are due to HMRC by the 22nd of the following month if you pay electronically (the 19th if you still post a cheque). Small employers can sometimes pay quarterly — check whether you qualify.

Year-end payroll: by 5 April / 31 May / 6 July. After the tax year ends, you finalise payroll, give employees a P60 by 31 May, and report any expenses and benefits (P11D) by 6 July.

Companies House filings (limited companies and LLPs)

These aren't tax — they go to Companies House, the public register of companies — but they're deadlines that carry penalties, so they belong here.

Confirmation statement: at least once every 12 months. This is a yearly "yes, our details are still correct" check-in. It confirms your directors, address and shareholders. There's a filing fee and a window to file it — miss it badly and the company can be struck off.

Annual accounts: within 9 months of your year-end (for a private company). Your first set after incorporating gets a longer window. These accounts are filed publicly, and even a dormant company that did no trading still has to file.

Tell them about changes promptly. New director, new registered address, new shares issued (an SH01) — these have their own short deadlines, usually within days or a couple of weeks.

A handy way to think about it: HMRC wants your money and your numbers; Companies House wants your facts kept current. Different masters, different dates.

Why staying on top of these matters (beyond avoiding fines)

The obvious reason to hit these dates is to dodge penalties and interest — and those add up fast. A late Self Assessment is an automatic fine the day after the deadline, whether or not you owed any tax. Late VAT and late filing at Companies House stack up their own charges.

But there's a quieter reason. A founder who knows their deadlines is a founder who isn't carrying low-level dread all year. The cost of missing a deadline isn't just the fine — it's the scramble, the weekend lost to digging through bank statements, the call to an accountant who's now charging emergency rates. Knowing what's coming, and having tidy records behind it, turns each deadline from a crisis into a five-minute job.

It also matters the moment anyone looks closely at your business. An investor or a lender glancing at your file will notice overdue tax or a struck-off warning instantly. Being up to date is the cheapest possible signal that you run a tight ship.

The short version

There are really six things to watch. Self Assessment (file and pay by 31 January). VAT (usually a month and seven days after each quarter). Corporation Tax (pay at nine months and a day; file at twelve). PAYE (report on payday, pay by the 22nd). Confirmation statement (yearly). Annual accounts (within nine months of year-end). Apply only the ones that fit your business, confirm the exact dates for your situation, and you're covered.

None of this requires you to become an accountant. It requires you to know which dates are yours — and to have records tidy enough that hitting them is quick.

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Ready to stop tracking all this on sticky notes? In Ledgers, your deadlines live in one compliance calendar, your VAT return and accounts are built automatically from your bank feed, and a Companies House tracker nudges you before each filing — so the dates stop being a source of dread. See your numbers without learning accounting → start free.

New to filing? Start here: Self Assessment for the terrified — a step-by-step →

Want the bigger picture first? Accounting for non-accountants: the plain-English guide for UK founders →

Frequently asked questions

When is the Self Assessment deadline in the UK?

For online returns, it's 31 January — you must both file the return and pay the tax owed for the previous tax year by midnight. If you owe payments on account, the second instalment is due 31 July.

When do I have to pay Corporation Tax?

Nine months and one day after your company's accounting year-end. The Company Tax Return itself is due within 12 months of year-end, so you pay before you file.

What happens if I miss a tax deadline in the UK?

HMRC charges automatic penalties plus interest — a late Self Assessment is fined the day after the deadline even if no tax is due. Late Companies House filings carry their own escalating fines. Confirm current penalty amounts with HMRC.

Do these deadlines change every year?

The dates (like 31 January) are mostly fixed, but the thresholds and rates around them — VAT registration threshold, tax bands, allowances — change regularly. Always confirm current figures with HMRC.

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