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2025 Accounting Calendar for Small Businesses

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Running a small business in the UK means juggling many responsibilities and keeping track of key accounting dates is one of the most crucial. Missing a tax filing or payment deadline can lead to fines, interest, or other penalties. This 2025 accounting calendar lays out all the important deadlines UK small businesses need to know. From 2025 accounting deadlines for UK small businesses related to Self Assessment and VAT, to PAYE payroll dates and Companies House filings, we’ve got you covered. Read on for a month-by-month guide and handy tips to stay compliant and avoid costly mistakes.

In this guide: We’ll break down the major tax and accounting deadlines in 2025 for UK startups and small businesses. You’ll find dates for Self Assessment tax returns, VAT quarters, PAYE payroll submissions, corporation tax payments, and Companies House filings like annual accounts and confirmation statements. We also explain what each deadline means and why it’s important to meet it on time. Let’s dive in!

Self Assessment and Income Tax Deadlines in 2025

Many small business owners (especially sole traders and company directors) need to file Self Assessment tax returns. Here are the key Self Assessment deadlines in 2025 and what they mean:

  • 31 January 2025 – Online Tax Return and Payment: This is the final deadline to submit your 2023/24 Self Assessment tax return online and pay any tax owed for that year (Tax year dates and deadlines UK 2025 | Sage Advice UK). 31 January is also when your first payment on account is due for the 2024/25 tax year (this is an advance payment towards your next year’s tax bill) (Tax year dates and deadlines UK 2025 | Sage Advice UK). In practice, many small business owners make two payments on their account each year (Jan 31 and July 31) to cover their upcoming tax liabilities.

  • 5 April 2025 – End of the Tax Year: The UK tax year 2024/25 ends on 5 April 2025. After this date, you can finalise your accounts for that year. (It’s also the deadline to make any claims or reliefs for the 2019/20 tax year if applicable, as there’s a four-year window for claiming overpaid tax.)

  • 6 April 2025 – New Tax Year Begins: The 2025/26 tax year starts on 6 April 2025. From this day, any income or expenses will count toward your 2025/26 return. It’s a good time to update your bookkeeping records and prepare for any new tax rules or rate changes that take effect (new personal allowance, National Insurance thresholds, etc.).

  • 31 July 2025 – Second Payment on Account: If you’re required to make payments on account, the second payment on account for 2024/25 is due by 31 July 2025 (Key Dates for SMEs in 2025 – Fleximize). This is the second half of the advance tax payment based on your 2023/24 liability. (The first half was paid in January.) If your 2023/24 tax bill was over £1,000 and less than 80% of your tax was collected at source, HMRC will have requested these payments on account (Small business accounting calendar 2025: key tax dates & deadlines – FreeAgent).

  • 5 October 2025 – Register for Self Assessment: If you started a new business or began receiving untaxed income in the 2024/25 tax year, you must register for Self Assessment by 5 October 2025. This applies if it’s your first time filing a return or you have a new source of income that requires Self Assessment (2025 Accounting Calendar for small businesses | Dojo). Failing to register by this date could lead to a late notification penalty ( Self Assessment tax returns: Penalties – GOV.UK ).

  • 31 October 2025 – Paper Tax Return Deadline: If you choose to file a paper tax return (postal submission for 2024/25), it must reach HMRC by 31 October 2025. Most businesses now file online, but if you use the paper form this earlier deadline is crucial to note.

  • 30 December 2025 – Coding Notice Deadline: For those who have a small tax balance (under £3,000) and want it collected through your PAYE tax code (i.e. through your salary in the next year), 30 December 2025 is the deadline to submit your 2024/25 tax return online and request this. This option is often used by directors who take a small salary and want any additional tax to be adjusted via PAYE.

  • 31 January 2026 – Final Online Filing Deadline (for 2024/25): Although it falls in the next calendar year, note that 31 January 2026 is the final deadline to file your 2024/25 Self Assessment return and pay any remaining tax for that year (Tax year dates and deadlines UK 2025 | Sage Advice UK). Missing this will immediately trigger late filing penalties. (We mention this now so you can mark it on your calendar as you plan for end-of-2025.)

Why these deadlines matter: Missing a Self Assessment deadline can result in an automatic £100 late filing penalty (even if you owe no tax), plus escalating fines if the delay continues ( Self Assessment tax returns: Penalties – GOV.UK ). Interest will also be charged on late payments. To avoid this, make sure to file your return and pay any tax by the due dates. If you think you’ll struggle to pay, contact HMRC early – they may arrange a payment plan to help, but you must still file on time to avoid penalties (Key Dates for SMEs in 2025 – Fleximize).

VAT Deadlines in 2025 (Quarterly and Annual)

If your business is VAT-registered, you’ll have regular VAT return and payment deadlines to meet. Most small businesses submit VAT returns quarterly, though some use annual or monthly schemes. Here are the key VAT dates in 2025 for the standard quarterly schedule:

Note: The above dates assume your VAT quarters follow the common schedule of quarter-ends in March, June, September, and December (Tax year dates and deadlines UK 2025 | Sage Advice UK). If your business has a different VAT stagger (e.g. quarter ends in January/April/July/October or Feb/May/Aug/Nov), your specific quarter-end dates and corresponding deadlines will differ. In all cases, the rule is that the VAT return and payment are due one month and 7 days after the end of your VAT period (Tax year dates and deadlines UK 2025 | Sage Advice UK). For example, if your VAT quarter ends 30 April, the deadline would be 7 June; if it ends 31 May, the deadline is 7 July, and so on (Tax year dates and deadlines UK 2025 | Sage Advice UK). Always double-check your VAT certificate or HMRC online account to confirm your stagger dates.

Annual VAT scheme: Some small businesses with turnover under £1.35 million use HMRC’s Annual Accounting Scheme, where you make advance payments and file one VAT return per year (Tax year dates and deadlines UK 2025 | Sage Advice UK). If you’re on annual VAT, your deadline will usually be 2 months after the end of your VAT year (for example, if your VAT year ends 31 March 2025, the annual return might be due by 31 May 2025 under that scheme). Make sure to verify the exact due date if you use annual accounting.

Why it matters: Missing a VAT deadline can have serious consequences. As of 2023, HMRC uses a points-based penalty system for late VAT returns. If you file or pay late, you may incur penalty points; multiple missed deadlines can lead to fines, and any late payment accrues interest. Moreover, consistent lateness could draw unwanted scrutiny to your business records. To stay compliant, submit VAT returns on time (via Making Tax Digital software, which is required for all VAT-registered businesses (Small business accounting calendar 2025: key tax dates & deadlines – FreeAgent)) and pay the VAT due by the deadline. Consider setting calendar reminders a week or two before each due date to give yourself time to compile your VAT figures and arrange payment.

PAYE and Payroll Deadlines in 2025

If your small business has employees (or you pay yourself as an employee/director), you need to follow PAYE (Pay As You Earn) and payroll deadlines throughout the year. These include regular reporting to HMRC and yearly tasks like issuing forms to employees. Here are the main payroll dates to note in 2025:

  • Every Month – PAYE Reporting and Payments: Payroll is a monthly cycle for most businesses. On or before each payday, you must submit a Full Payment Submission (FPS) to HMRC, reporting wages and deductions for that pay period (Tax year dates and deadlines UK 2025 | Sage Advice UK). If no employees were paid in a given month, you’d send an Employer Payment Summary (EPS) instead. In addition, you need to pay the income tax and National Insurance you’ve deducted (plus any employer NICs) to HMRC. The payment deadlines are 22nd of each month for electronic payments (or 19th of the month if paying by cheque) for the previous tax month (Tax year dates and deadlines UK 2025 | Sage Advice UK). For example, PAYE deductions for January 2025 (covering wages in the tax month 6 Jan – 5 Feb) should be paid by 22 Feb 2025 if paying electronically (Tax year dates and deadlines UK 2025 | Sage Advice UK). Most small businesses pay electronically, so mark the 22nd of each month as your PAYE deadline. Missing these monthly PAYE payments could trigger late payment penalties and interest, so it’s wise to stay on top of them.

  • 6 April 2025 – Start of New Payroll Year: The new tax year means new payroll records. By 6 April, make sure you update your employee payroll records for 2025/26 (Key Dates for SMEs in 2025 – Fleximize). This includes applying new tax codes (HMRC will issue new codes if employees’ tax allowances change), and updating any changes to National Insurance thresholds, student loan deductions, or statutory pay rates (note: April 2025 is expected to bring increases to National Minimum Wage and various statutory payments (Key Dates for SMEs in 2025 – Fleximize), so ensure your payroll software is updated accordingly).

  • 19 April 2025 – Final 2024/25 RTI Submission: As part of your payroll year-end process for 2024/25, you need to submit your final Real Time Information (RTI) reports by 19 April 2025 (Key Dates for SMEs in 2025 – Fleximize) (Tax year dates and deadlines UK 2025 | Sage Advice UK). In practice, this usually means marking your last FPS of the tax year (on or before 5 April) as the “final submission” or sending a final EPS. By 19 April, you should also pay over any remaining PAYE tax or National Insurance for 2024/25 to HMRC (Key Dates for SMEs in 2025 – Fleximize). This ensures the tax year is closed off correctly.

  • 31 May 2025 – Distribute P60s to Employees: P60 forms summarize an employee’s total pay and deductions for the tax year. You must give a P60 to every employee who was on your payroll at the end of the tax year (5 April 2025) by 31 May 2025  (Tax year dates and deadlines UK 2025 | Sage Advice UK). This is a legal requirement – employees need their P60s for their records and possibly for self-assessment or tax credit purposes. Make sure you prepare these in time (your payroll software can usually generate them).

  • 5 July 2025 – PAYE Settlement Agreement (PSA) Finalisation: If you have a PAYE Settlement Agreement in place (an arrangement with HMRC to cover minor, irregular, or impracticable benefits and expenses for your employees in one annual payment), 5 July 2025 is generally the last day to finalise or agree any PSA for the 2024/25 year. Under a PSA, the employer pays the tax and National Insurance on those items on behalf of employees, and 5 July is the date by which HMRC expects the PSA agreement to be in place.

  • 6 July 2025 – P11D and Benefits Reporting: By 6 July each year, employers must report employee benefits and expenses for the prior tax year. This means you need to file P11D forms for any employees (including directors) who received benefits in kind during 2024/25 (for example, company cars, health insurance, travel or entertainment expenses not reimbursed, etc.). You also need to submit a P11D(b) form which is the summary of all P11Ds and calculates the Class 1A National Insurance due on those benefits (Key Dates for SMEs in 2025 – Fleximize) (Tax year dates and deadlines UK 2025 | Sage Advice UK). Additionally, you must give employees a copy of their individual P11D so they know what has been reported. 6 July 2025 is the deadline for both filing these forms with HMRC and providing the information to employees.

  • 19/22 July 2025 – Class 1A NICs Payment: After filing P11Ds, the employer needs to pay the Class 1A National Insurance Contributions on the total benefits provided. The payment deadline is 19 July 2025 if paying by post (cheque), or 22 July 2025 if paying electronically (Tax year dates and deadlines UK 2025 | Sage Advice UK). Most will use the electronic deadline. This Class 1A NIC covers the employer’s national insurance on benefits reported on P11Ds for 2024/25. Mark 22 July on your calendar to ensure this payment is sent, as missing it can incur interest and penalties.

  • Ongoing PAYE tasks: Aside from these specific dates, remember to keep your payroll records up to date monthly, issue payslips to employees each payday, and report any new starters or leavers promptly (in the FPS submissions). If you operate in the construction industry and subcontract work, you’ll also have monthly CIS returns to submit (due by the 19th of each month for the previous month’s CIS deductions). Always maintain good payroll practices to avoid compliance issues – HMRC can charge penalties for late or inaccurate payroll reports as well.

Why it matters: Payroll deadlines are just as important as tax return deadlines. Late monthly PAYE payments can trigger fines, and failing to file P11Ds or provide P60s on time can result in penalties (for instance, there are £100 per 50 employees penalties for late P11D submissions). Staying on schedule keeps your employees happy (they get their documents on time) and keeps HMRC off your back. If you use a payroll software or have an accountant, leverage their reminder features for these key dates. Always reconcile your payroll at year-end to make sure all taxes due have been paid over – it’s easier to sort out discrepancies sooner than later.

Corporation Tax and Company Accounts Deadlines (Limited Companies)

If you run a limited company in the UK, there are additional deadlines for corporation tax and filings with Companies House. These don’t necessarily fall on the same date every year for everyone – they depend on your company’s financial year-end (also called your accounting reference date). Here are the general rules and some common examples to help you plan in 2025:

  • Corporation Tax Payment – 9 Months After Year-End: A company must pay its corporation tax bill 9 months and 1 day after the end of its accounting period (A Guide to Limited Company Tax Deadlines – Fleximize). In practice, this usually works out to 9 months after the financial year-end (for a normal 12-month trading period). For example, if your company’s financial year ended 31 March 2024, your corporation tax payment for that period is due by 1 January 2025 (Small business accounting calendar 2025: key tax dates & deadlines – FreeAgent). Similarly, if your financial year ends 31 December 2024, the corporation tax for that year must be paid by 1 October 2025 (9 months and a day after 31 Dec 2024). Many small businesses align their year-end with the tax year (31 March or 5 April) or the calendar year (31 December), so these are common scenarios. Check your own year-end and count 9 months forward to find your payment deadline. Mark that date in 2025 if it applies. (If you have profits over £1.5 million, note that corporation tax is paid in quarterly installments, but most small companies pay annually.)

  • Company Accounts Filing – 9 Months After Year-End: Private limited companies must also file annual accounts with Companies House within 9 months after the year-end date (A Guide to Limited Company Tax Deadlines – Fleximize). This deadline often coincides closely with the corporation tax payment deadline. Using the same examples: a company with year-end 31 March 2025 must file its accounts by 31 December 2025 (Small business accounting calendar 2025: key tax dates & deadlines – FreeAgent). A company with year-end 31 December 2024 must file accounts by 30 September 2025 (9 months after 31 Dec). Companies House will have informed you of your Accounting Reference Date, and it usually stays the same each year (unless you change it). Note: For a company’s first set of accounts after incorporation, the deadline can be slightly longer (usually 21 months from incorporation) (A Guide to Limited Company Tax Deadlines – Fleximize), but afterward it’s 9 months. Filing accounts late incurs an automatic financial penalty, ranging from £150 for just a day late up to £1,500 for over 6 months late (A Guide to Limited Company Tax Deadlines – Fleximize). These fines are applied even if the company owes no tax or is dormant, so it’s crucial to file on time.

  • Company Tax Return (CT600) – 12 Months After Year-End: Apart from paying the tax, you also need to file a Company Tax Return (form CT600 with detailed accounts and calculations) to HMRC. This is due 12 months after the end of the accounting period (Tax year dates and deadlines UK 2025 | Sage Advice UK). In practical terms, you’ll likely be filing the CT600 at the same time as preparing your annual accounts. For example, if your year-end was 31 March 2024, the CT600 return is due by 31 March 2025 (Small business accounting calendar 2025: key tax dates & deadlines – FreeAgent). If your year-end is 31 December 2024, the CT600 is due by 31 December 2025. Important: The CT600 filing deadline is separate from the payment deadline – you pay the tax by month 9, but you have until month 12 to file the full return (Tax year dates and deadlines UK 2025 | Sage Advice UK). Do not confuse the two. In practice, many companies file both accounts and CT600 together before the earlier deadline (9 months) which is good discipline. But you technically have a bit more time for the tax return itself (just don’t miss it, as late filing of a corporation tax return can lead to HMRC penalties starting at £100 and increasing over time (A Guide to Limited Company Tax Deadlines – Fleximize)).

  • Confirmation Statement – Annual (usually incorporation anniversary): Every UK company must file a Confirmation Statement (CS01) with Companies House at least once every 12 months (Tax year dates and deadlines UK 2025 | Sage Advice UK). This isn’t tied to the tax year; it’s based on either the anniversary of incorporation or the date you last filed a confirmation statement. The confirmation statement is basically a snapshot to confirm your company’s details (directors, registered address, shareholders, etc.) and report any changes. The deadline is usually 12 months from your last confirmation statement (or incorporation), and Companies House gives a 14-day grace period after the due date to submit it (Tax year dates and deadlines UK 2025 | Sage Advice UK). For example, if you incorporated a company on 15 June 2024, your first confirmation statement due date will be 15 June 2025 (you then have 14 days to file it, i.e. by 29 June 2025). If you filed last year’s statement on 10 September 2024, then by 10 September 2025 you need to file the next one. Mark your particular due date, as it varies by company. There is a fee (currently £13 if filed online) each time you file a confirmation statement. While there’s no hefty fine structure like tax filings, failing to file a confirmation statement can result in your company being struck off the register, which is far worse. So make sure you don’t forget this annual requirement (Tax year dates and deadlines UK 2025 | Sage Advice UK).

Tips for Companies: It’s wise to create a company calendar of these specific deadlines based on your year-end. Many small companies align their year-end with either March 31 or December 31 for simplicity. If you do, the above examples give you your deadlines in 2025. If you have an alternate year-end (say 30 June or 30 September), adjust accordingly: e.g., a 30 June 2024 year-end means tax due 1 April 2025 and accounts/CT600 due 30 March 2025 (accounts) and 30 June 2025 (CT600) – which actually means those fall in early 2025 for the tax and late 2025 for the return. Whatever the case, plan ahead so you’re not scrambling near the deadline. It’s common to have your accountant prepare statutory accounts and CT600 well before the due date, to allow time for review and making the payment. Remember that both HMRC and Companies House have to receive different filings, so ensure you meet both obligations. Missing company accounts filing triggers an automatic fine from Companies House as mentioned (A Guide to Limited Company Tax Deadlines – Fleximize), and if you delay too long they can even move to dissolve your company. Missing the corporation tax payment will accrue interest daily, and HMRC can charge late payment penalties if the tax is overdue by 6 or 12 months ( Self Assessment tax returns: Penalties – GOV.UK ). In short, don’t let these slip – diarise them and get them done early if possible.

Staying Compliant and Avoiding Penalties

Keeping track of all these deadlines might feel daunting, but it’s absolutely manageable with a bit of organisation and the right tools. Here are some final tips to ensure you stay compliant throughout 2025 and avoid costly penalties:

  • Mark Your Calendar: Use a digital calendar (or the downloadable table below) to mark all relevant deadlines for the year. Set reminders at least a week in advance. This 2025 accounting calendar should be a living document for your business – refer to it at the start of each month to see what’s coming up. Many small business owners find it helpful to schedule time (e.g., a day each quarter) to work on VAT or accounts well before the due date, so the deadline isn’t a last-minute rush.

  • Use Software and Alerts: If you’re using accounting software (like QuickBooks, Xero, FreeAgent, etc.), take advantage of built-in reminder features. HMRC’s online systems can also send email reminders for some filings (for example, they often send reminders for VAT return due dates if you’re enrolled for digital alerts). There are also specialist deadline tracking apps that can keep all these dates in one place. The key is to automate your reminders so you’re less likely to forget a requirement.

  • Get Professional Help if Needed: Don’t hesitate to involve an accountant or bookkeeper, especially if you’re a new startup. They can help you set up a compliance calendar and even handle filings on your behalf. As one expert piece of advice says, if you’re unsure of your obligations, working with an accountant can provide extra clarity on what taxes you need to file and when (Small business accounting calendar 2025: key tax dates & deadlines – FreeAgent). This can be invaluable in avoiding accidental missed deadlines.

  • Stay Educated on Changes: Tax rules can change year to year. For instance, 2025 might bring new thresholds or a new penalty regime (the VAT penalty system recently changed, for example). Keep an eye on HMRC updates or consult your accountant whenever a new tax year starts. By knowing what’s coming, you won’t be caught off guard by an unusual deadline or requirement.

  • Penalties are Expensive – Avoid Them: Always remember the cost of non-compliance far exceeds the effort to comply. For example, filing a Self Assessment return late by just a day costs £100 ( Self Assessment tax returns: Penalties – GOV.UK ); a late company accounts filing starts at £150 and can reach £1,500 (A Guide to Limited Company Tax Deadlines – Fleximize); not to mention HMRC can charge interest on overdue taxes and even additional surcharges (for instance, a 5% charge on tax unpaid after 30 days, 6 months, etc.) ( Self Assessment tax returns: Penalties – GOV.UK ). These are wasted expenses – money that could be invested back into your business. By meeting deadlines, you keep that money in your business and maintain a clean compliance record.

  • Plan for Cash Flow Around Deadlines: Some deadlines involve paying large sums (tax bills, VAT payments). It’s prudent to set aside funds throughout the year for these. For instance, you know in January and July you have Self Assessment payments – ensure you have saved for that in advance. Same for corporation tax – don’t wait until 8 months into the year to realise you owe a big chunk. Good accounting practice is to accrue for taxes so you’re prepared when the due date arrives (Key Dates for SMEs in 2025 – Fleximize). This avoids panic or needing emergency financing to meet tax obligations.

By staying organised and proactive, you can master the 2025 accounting calendar instead of letting it master you. Compliance is simply part of running a successful business. When you file everything on time and pay what’s due, you can focus on what you do best – growing your venture – without worrying about HMRC brown envelopes showing up unexpectedly.

2025 Accounting Deadlines at a Glance (Downloadable Calendar)

For a convenient overview, here’s a month-by-month 2025 accounting calendar highlighting key dates. You can save or print this table as a quick reference:

Month 2025Key Deadlines & Filings
January

– 1 Jan: Corporation Tax payment due for companies with 31 Mar 2024 year-end

– 31 Jan: Self Assessment 2023/24 online filing deadline and tax payment due (balancing payment)

February– 7 Feb: VAT return due for Q4 2024 (Oct–Dec 2024 period) 
March

– 19 Mar: PAYE/NIC payment (electronic) due for month ending 5 Mar 2025.

– 31 Mar: Corporation Tax return (CT600) due for companies with 31 Mar 2024 year-end (12 months after year-end). (Also, companies with 30 June 2024 year-end should pay corporation tax by 1 April 2025.)

April– 5 Apr: End of 2024/25 tax year ([2025 Accounting Calendar for small businesses
May

– 7 May: VAT return due for Q1 2025 (Jan–Mar 2025 period)

– 22 May: PAYE/NIC payment due for month ending 5 May 2025.

– 31 May: P60s must be given to all employees for 2024/25 

June– 7 Jun: (If applicable) VAT return due for quarter Feb–Apr 2025 (for businesses on stagger 2 VAT periods)
July– 5 Jul: Finalise any PAYE Settlement Agreement (PSA) for 2024/25 (if using a PSA)
August

– 7 Aug: VAT return due for Q2 2025 (Apr–Jun 2025 period).

– 22 Aug: PAYE/NIC payment due for month ending 5 Aug 2025.

September

– 7 Sep: (If applicable) VAT return due for quarter May–Jul 2025 (stagger 2 period).

– 22 Sep: PAYE/NIC payment due for month ending 5 Sep 2025.

October– 5 Oct: Register for Self Assessment by this date if you have new income in 2024/25 and haven’t registered before 
November– 7 Nov: VAT return due for quarter ending 30 Sept 2025 (Jul–Sep, standard stagger Q3)
December– 30 Dec: Deadline to submit 2024/25 tax return online if you want any tax under £3,000 coded into your 2026/27 PAYE code

(Note: The above table highlights many common deadlines, but your business may have others specific to your circumstances. Always double-check your own dates with HMRC and Companies House.)

As the year progresses, refer back to this calendar and ensure each item is checked off. Staying compliant with all filings – be it tax returns, VAT, payroll, or accounts – will give you peace of mind and let you focus on running your business. By proactively managing the 2025 accounting deadlines, UK small businesses can avoid penalties and thrive in the year ahead (Key Dates for SMEs in 2025 – Fleximize). Here’s to a successful and stress-free financial year!

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