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:

CycleRuns fromRuns toWho it applies to
Company financial yearYour accounting reference date12 months laterLimited companies
Tax year6 April5 AprilEveryone – 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:

DeadlineWhatWhere to filePenalty for missing
31 December (9 months)File annual accountsCompanies House£150 (rising to £1,500 if 6+ months late)
1 January (9 months and 1 day)Pay Corporation TaxHMRCInterest 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 statementCompanies 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 latePrivate company penaltyPublic 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 latePenalty
1 day£100
3 monthsAnother £100
6 monthsHMRC estimates your tax bill and charges 10% of unpaid tax
12 monthsAnother 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:

InstalmentDue date (months after period start)
1st6 months and 13 days
2nd9 months and 13 days
3rd12 months and 13 days (after period start, i.e., 13 days after period end)
4th15 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

TaskDeadline
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 HMRC22nd of the following month (electronic) or 19th (by post)

Annual deadlines (after 5 April)

TaskDeadlinePenalty
Final FPS for the tax yearOn or before 5 April (or last pay date)£100 per 50 employees per month late
P60s to employees31 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 JulySame as P11D
Pay Class 1A NIC22 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:

DeadlineWhat
5 OctoberRegister for Self Assessment if you have a new source of income
31 OctoberPaper tax return deadline (rarely used now)
31 JanuaryOnline tax return deadline AND payment of balancing tax AND first payment on account
31 JulySecond 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).

TaskDeadline
File VAT return1 month and 7 days after the end of the VAT period
Pay VATSame 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:

DateWhat to do
5 AprilTax year ends – final payroll for the year
6 AprilNew tax year begins – apply new tax codes
22 AprilPay March PAYE/NIC to HMRC
31 MayIssue P60s to employees
6 JulyFile P11Ds and P11D(b)
22 JulyPay Class 1A NIC
31 JulySelf Assessment second payment on account
5 OctoberRegister for Self Assessment (new sources of income)
31 DecemberFile annual accounts at Companies House
1 JanuaryPay Corporation Tax to HMRC
31 JanuarySelf Assessment online deadline and first payment on account
31 MarchFile 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.