UK Tax Calendar 2025/26: Every Deadline You Need to Know

Missing a tax deadline in the UK does not just mean a stern letter from HMRC — it means automatic penalties, interest charges, and unnecessary stress. Whether you are a sole trader, limited company director, or employer, knowing your key dates is fundamental to staying compliant and avoiding costly fines.

This calendar covers the 2025/26 tax year (6 April 2025 to 5 April 2026) and includes all major HMRC and Companies House deadlines.

Key Dates at a Glance

Date	Deadline	Applies To
5 April 2025	End of 2024/25 tax year	Everyone
6 April 2025	Start of 2025/26 tax year	Everyone
19 April 2025	Final PAYE payment for 2024/25 (postal)	Employers
22 April 2025	Final PAYE payment for 2024/25 (electronic)	Employers
31 May 2025	P60s issued to employees for 2024/25	Employers
6 July 2025	P11D and P11D(b) deadline for 2024/25	Employers
19 July 2025	Class 1A NIC payment (postal) for 2024/25	Employers
22 July 2025	Class 1A NIC payment (electronic) for 2024/25	Employers
31 July 2025	Second payment on account for 2024/25 Self Assessment	Individuals
5 October 2025	Notify HMRC of new self-employment or income source	Individuals
31 October 2025	Paper Self Assessment return deadline for 2024/25	Individuals
31 January 2026	Online Self Assessment return deadline for 2024/25	Individuals
31 January 2026	Balancing payment for 2024/25 Self Assessment	Individuals
31 January 2026	First payment on account for 2025/26	Individuals

Self Assessment Deadlines Explained

Self Assessment affects sole traders, company directors, landlords, and anyone with income over £150,000 or untaxed income.

For the 2024/25 tax year:

• 31 October 2025 — deadline for paper Self Assessment returns (rarely used now)
• 31 January 2026 — deadline for online Self Assessment returns
• 31 January 2026 — pay any tax owed for 2024/25 plus the first payment on account for 2025/26
• 31 July 2026 — second payment on account for 2025/26

Penalties for late filing:

• 1 day late: £100 automatic penalty
• 3 months late: £10 per day for up to 90 days (maximum £900)
• 6 months late: £300 or 5% of tax due, whichever is greater
• 12 months late: a further £300 or 5% of tax due

Late payment interest runs at the Bank of England base rate plus 2.5%. As of early 2025, this is approximately 7% — a powerful incentive to pay on time.

Corporation Tax Deadlines

Corporation Tax deadlines are based on your company's accounting period end date, not the tax year:

• CT600 filing deadline: 12 months after the end of the accounting period
• Corporation Tax payment deadline: 9 months and 1 day after the end of the accounting period

Example for a 31 March 2025 year-end:

• Tax payment due: 1 January 2026
• CT600 filing due: 31 March 2026

Note that the payment deadline comes before the filing deadline. Many directors are caught out by this, paying a tax bill they have not yet calculated. It is wise to prepare your accounts well ahead of the payment date.

Penalties for late CT600 filing:

• 1 day late: £100
• 3 months late: another £100
• 6 months late: HMRC estimates your tax and adds 10% of the unpaid amount
• 12 months late: a further 10% of unpaid tax

Companies House Deadlines

These are separate from HMRC and carry their own penalties:

Annual Accounts:

• Must be filed within 9 months of the accounting reference date (for private companies)
• Late filing penalties range from £150 (up to 1 month late) to £1,500 (over 6 months late)

Confirmation Statement:

• Due at least once every 12 months from the anniversary of incorporation or the last statement
• Filing fee: £34 (online) or £62 (paper)
• Failure to file can lead to the company being struck off the register

VAT Deadlines

If your business is VAT registered, returns and payments follow a regular quarterly cycle:

• VAT returns are due 1 month and 7 days after the end of each quarter
• Payment must reach HMRC by the same date (direct debit allows 3 extra working days)

Standard VAT quarters and their deadlines:

Quarter End	Return & Payment Due
31 March	7 May
30 June	7 August
30 September	7 November
31 December	7 February

VAT registration threshold (2025/26): £90,000 — you must register if your taxable turnover exceeds this in any rolling 12-month period.

Making Tax Digital (MTD) requires all VAT-registered businesses to keep digital records and file returns using compatible software.

PAYE and Payroll Deadlines

If you employ staff (including yourself as a director), these dates are critical:

Monthly obligations:

• RTI submissions (Full Payment Submission) — on or before each payday
• PAYE/NIC payments — by the 22nd of the following month (electronic) or 19th (postal)

Annual obligations:

• P60s to employees — by 31 May
• P11D (benefits in kind) — by 6 July
• P11D(b) (Class 1A NIC summary) — by 6 July
• Class 1A NIC payment — by 22 July (electronic) or 19 July (postal)

Monthly Compliance Checklist

To stay on top of everything, here is a monthly routine:

• Every month: Submit RTI on or before payday, pay PAYE/NIC by 22nd
• Every quarter (if VAT registered): File VAT return and pay by the 7th of the month after the quarter-end plus one month
• Annually: File Self Assessment, CT600, annual accounts, Confirmation Statement, P11D
• Ongoing: Monitor turnover for VAT registration threshold

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This article is for informational purposes only and does not constitute tax advice.