Missing a deadline costs money. Companies House charges automatic late filing penalties starting at £150 and rising to £1,500. HMRC charges penalties plus daily interest on late payments. Knowing every date in advance and working backwards from the earliest deadline is the simplest way to avoid this.
The two year ends
UK businesses deal with two overlapping cycles:
| Cycle | Runs from | Runs to | Who it applies to |
|---|---|---|---|
| Company financial year | Your accounting reference date | 12 months later | Limited companies |
| Tax year | 6 April | 5 April | Everyone – individuals, PAYE, Self Assessment |
Your company’s accounting reference date is set at incorporation. You can choose any date, but the most common choices are 31 March (aligns closely with the tax year), 31 December (calendar year) and 30 September (avoids the busy January period for accountants).
For a detailed explanation of how these two cycles interact, see our guide on the UK year-end process.
Limited company deadlines
All deadlines below are measured from your accounting reference date (financial year end). If your year end is 31 March, the deadlines are as follows:
| Deadline | What | Where to file | Penalty for missing |
|---|---|---|---|
| 31 December (9 months) | File annual accounts | Companies House | £150 (rising to £1,500 if 6+ months late) |
| 1 January (9 months and 1 day) | Pay Corporation Tax | HMRC | Interest from the due date, plus surcharges |
| 31 March (12 months) | File CT600 (Company Tax Return) | HMRC | £100 immediately, £200 after 3 months, then 10% of tax owed after 6 and 12 months |
| 31 March (12 months) | File confirmation statement | Companies House (at least once per 12 months) | Criminal offence; company may be struck off |
Companies House late filing penalties
The penalties escalate automatically with no appeal for “I forgot”:
| How late | Private company penalty | Public company penalty |
|---|---|---|
| Up to 1 month | £150 | £750 |
| 1 to 3 months | £375 | £1,500 |
| 3 to 6 months | £750 | £3,000 |
| Over 6 months | £1,500 | £7,500 |
If you filed late the previous year as well, the penalties double.
HMRC late filing penalties for CT600
| How late | Penalty |
|---|---|
| 1 day | £100 |
| 3 months | Another £100 |
| 6 months | HMRC estimates your tax bill and charges 10% of unpaid tax |
| 12 months | Another 10% of unpaid tax |
These penalties apply on top of each other, so a CT600 filed 12 months late attracts £200 in flat penalties plus 20% of the unpaid tax.
Corporation Tax payment
Corporation Tax is due 9 months and 1 day after your accounting period ends. There is no separate reminder from HMRC – you are expected to calculate and pay the correct amount by the deadline.
If your taxable profits exceed £1.5 million, you must pay in quarterly instalments instead. The instalments start during the accounting period itself, not after it ends:
| Instalment | Due date (months after period start) |
|---|---|
| 1st | 6 months and 13 days |
| 2nd | 9 months and 13 days |
| 3rd | 12 months and 13 days (after period start, i.e., 13 days after period end) |
| 4th | 15 months and 13 days |
The current Corporation Tax rates are 19% on profits up to £50,000, a marginal rate between £50,000 and £250,000, and 25% on profits above £250,000.
PAYE and payroll deadlines
The PAYE tax year runs from 6 April to 5 April. If you have employees (including yourself as a director), you have monthly and annual obligations.
Monthly deadlines
| Task | Deadline |
|---|---|
| Submit Full Payment Submission (FPS) | On or before each pay date |
| Submit Employer Payment Summary (EPS) | By the 19th of the following month (only if no employees were paid) |
| Pay PAYE and NIC to HMRC | 22nd of the following month (electronic) or 19th (by post) |
Annual deadlines (after 5 April)
| Task | Deadline | Penalty |
|---|---|---|
| Final FPS for the tax year | On or before 5 April (or last pay date) | £100 per 50 employees per month late |
| P60s to employees | 31 May | £300 per occurrence |
| P11D (benefits in kind) | 6 July | £300 per form, plus up to £3,000 |
| P11D(b) (Class 1A NIC return) | 6 July | Same as P11D |
| Pay Class 1A NIC | 22 July (electronic) | Interest from due date |
Real Time Information (RTI)
Under RTI, you report payroll information to HMRC every time you pay an employee, not at the end of the year. Late FPS submissions trigger automatic penalties of £100 per 50 employees for each month (or part month) that the submission is late.
Self Assessment deadlines
If you are a sole trader, a partner, a company director with untaxed income, or anyone else who files Self Assessment, these are your key dates:
| Deadline | What |
|---|---|
| 5 October | Register for Self Assessment if you have a new source of income |
| 31 October | Paper tax return deadline (rarely used now) |
| 31 January | Online tax return deadline AND payment of balancing tax AND first payment on account |
| 31 July | Second payment on account |
Payments on account
If your Self Assessment tax bill is over £1,000 and less than 80% of it was collected at source (through PAYE), you must make payments on account. Each payment is 50% of the previous year’s bill:
- 31 January – first payment on account for the current year, plus any balancing payment for the previous year
- 31 July – second payment on account for the current year
This means 31 January is often a double hit: you pay the balance for last year and the first instalment for this year at the same time.
VAT deadlines
If you are VAT-registered, you must file returns and pay VAT quarterly (or monthly/annually depending on your scheme).
| Task | Deadline |
|---|---|
| File VAT return | 1 month and 7 days after the end of the VAT period |
| Pay VAT | Same date (or 1 month if paying by direct debit, with the payment taken 3 working days later) |
Under Making Tax Digital, all VAT-registered businesses must file digitally using compatible software. The penalty regime for late VAT returns uses a points-based system – you accumulate points for each late submission, and once you reach the threshold (4 points for quarterly filers), you receive a £200 penalty for that and every subsequent late return until you reset.
Late payment penalties for VAT
Since January 2023, late VAT payments attract:
- No penalty if paid within 15 days of the due date
- 2% of outstanding VAT if paid between 16 and 30 days late
- 2% of VAT outstanding at day 15 plus 2% of VAT outstanding at day 30 plus daily interest if paid after 30 days
Annual calendar summary
Here is every key date in one view, assuming a 31 March financial year end:
| Date | What to do |
|---|---|
| 5 April | Tax year ends – final payroll for the year |
| 6 April | New tax year begins – apply new tax codes |
| 22 April | Pay March PAYE/NIC to HMRC |
| 31 May | Issue P60s to employees |
| 6 July | File P11Ds and P11D(b) |
| 22 July | Pay Class 1A NIC |
| 31 July | Self Assessment second payment on account |
| 5 October | Register for Self Assessment (new sources of income) |
| 31 December | File annual accounts at Companies House |
| 1 January | Pay Corporation Tax to HMRC |
| 31 January | Self Assessment online deadline and first payment on account |
| 31 March | File CT600 with HMRC |
Staying on track
The number of deadlines can feel overwhelming, but most of them follow a predictable pattern year after year. Set calendar reminders at least one month before each deadline so you have time to prepare rather than scrambling on the last day.
Using accounting software that tracks your filing obligations and sends automated reminders removes much of the cognitive load. If your year-end accounts are prepared on time, everything else follows naturally.