Running a small business means juggling customers, suppliers, staff, cash flow and everything else that comes with being your own boss.

Unfortunately, HMRC deadlines do not disappear just because you are busy.

Missing a tax or filing deadline can lead to penalties, interest and unnecessary stress, so knowing the key dates in advance is one of the simplest ways to keep your business finances under control.

Here are some of the main tax deadlines UK small business owners should be aware of.

Self Assessment – 31 January

For sole traders, landlords, company directors and others who need to complete a Self Assessment tax return, 31 January is one of the most important dates in the tax calendar.

For the 2025/26 tax year, the deadline for filing your online Self Assessment tax return is:

31 January 2027

This is also normally the deadline for paying:

• any Income Tax and National Insurance due for 2025/26; and
• your first payment on account towards the 2026/27 tax year, where applicable.

NOTE: If you are filing a paper tax return, the deadline is earlier: 31 October 2026.

Try not to leave your tax return until January

Although the deadline is in January, you can prepare your tax return as soon as the tax year ends on 5 April.

Completing it earlier gives you more time to:

• understand how much tax you owe
• plan your cash flow
• check whether anything is missing
• avoid the January rush

NOTE: Submitting your tax return early does not mean you have to pay the tax early.

Payments on Account – 31 January and 31 July

If you are self-employed and your tax bill meets the relevant criteria, HMRC may ask you to make payments on account towards your next tax bill.

These are normally paid in two instalments:

31 January

and

31 July

This often catches new business owners by surprise.

For example, your January bill could include both the outstanding tax for the previous year and an advance payment towards the next year.

Good tax planning can help make sure this does not come as an unpleasant surprise.

Making Tax Digital for Income Tax – Quarterly Deadlines

Making Tax Digital for Income Tax became mandatory from 6 April 2026 for qualifying sole traders and landlords with relevant qualifying income over £50,000.

Instead of only dealing with HMRC once a year, those within MTD must maintain digital accounting records and send quarterly updates using compatible software.

The standard quarterly deadlines are:

• 7 August
• 7 November
• 7 February
• 7 May

For the 2026/27 tax year, the first quarterly deadline was 7 August 2026, followed by 7 November 2026, 7 February 2027 and 7 May 2027.

The quarterly updates do not replace your annual tax return. You will still need to complete your year-end tax submission.

HMRC has confirmed that penalty points will not be issued for late quarterly MTD updates during the 2026/27 tax year, although the updates still need to be submitted before the annual tax return can be completed.

VAT Returns – Usually Every Three Months

If your business is VAT registered, you will usually submit a VAT return every three months.

The deadline is generally:

One month and seven days after the end of the VAT period.

For example, if your VAT quarter ends on 31 March, your VAT return and payment would normally be due by 7 May.

VAT deadlines will vary depending on the VAT quarters allocated to your business, so it is important to check your own VAT schedule rather than relying on another business's dates.

Keeping your bookkeeping up to date throughout the quarter makes preparing your VAT return much easier.

PAYE and Payroll Deadlines

If you employ staff, payroll brings its own set of regular deadlines.

Your Full Payment Submission (FPS) should normally be sent to HMRC on or before the date you pay your employees.

PAYE and National Insurance collected through payroll is then usually payable to HMRC by the:

22nd of the following month if paying electronically.

For businesses that qualify to pay PAYE quarterly, different payment dates can apply.

Payroll errors can affect not only your business but also your employees' tax records, pensions and benefits, so this is one area where being organised is particularly important.

Corporation Tax Payment – 9 Months and 1 Day

Limited companies have different deadlines from sole traders.

For most small companies, Corporation Tax must be paid:

9 months and 1 day after the end of the Corporation Tax accounting period.

For example, if your company's year end is:

31 March 2026

the Corporation Tax payment deadline would normally be:

1 January 2027

An important point to remember is that the tax is normally due before the Corporation Tax return itself has to be filed.

Corporation Tax Return – 12 Months

Your company's Corporation Tax Return must usually be submitted to HMRC:

12 months after the end of the accounting period.

So, using the same company with a 31 March 2026 year end, the Corporation Tax Return would normally need to be filed by:

31 March 2027

Even if your company has made a loss or has no Corporation Tax to pay, you may still be required to file a Company Tax Return if HMRC has issued a notice requiring one.

Companies House Accounts – Usually 9 Months

Limited companies also need to file annual accounts with Companies House.

For most private limited companies, the deadline is:

9 months after the company's financial year end.

For example:

Company year end: 31 March 2026

Companies House filing deadline: 31 December 2026

Different rules apply to a company's first set of accounts. A private company's first accounts are generally due 21 months after incorporation, although the exact deadline depends on the accounting period.

Confirmation Statement – Every Year

Every UK limited company must also submit a Confirmation Statement to Companies House.

This confirms important company information such as:

• registered office
• directors
• shareholders
• people with significant control
• share capital
• certain business information

Your Confirmation Statement date is specific to your company, so this is not one universal annual deadline.

It is important not to confuse the Confirmation Statement with your annual accounts. They are separate filing obligations.

Your Company's Deadlines May Be Different

One of the reasons business deadlines can become confusing is that not every business follows exactly the same calendar.

Your deadlines may depend on:

• whether you are a sole trader or limited company
• your company's financial year end
• your VAT quarters
• whether you operate payroll
• whether you fall within Making Tax Digital
• your personal Self Assessment circumstances

This is why simply copying dates from another business owner is rarely a good idea.

Missing a Deadline Can Cost You

Leaving things until the last minute can result in:

• late filing penalties
• late payment penalties
• interest
• Companies House penalties
• HMRC correspondence
• cash-flow problems
• unnecessary stress

More importantly, repeatedly preparing your accounts at the last minute makes it difficult to use the financial information to actually manage your business.

Your accounts should tell you what is happening in your business — not simply become something you deal with when HMRC asks for them.

A Simple Way to Stay Ahead

A good routine is to keep your bookkeeping updated throughout the year rather than trying to reconstruct everything just before a deadline.

Ideally:

• reconcile your bank regularly
• upload receipts as you receive them
• review outstanding invoices
• keep payroll information up to date
• set money aside for tax
• speak to your accountant before making major financial decisions

The earlier we have accurate information, the more opportunity there is to identify problems and consider tax-planning opportunities.

Need Help Keeping Track of Your Business Deadlines?

At Partridge Accountancy Services, we help sole traders and limited companies stay on top of their accounts, VAT, payroll, Corporation Tax, Self Assessment and Making Tax Digital obligations.

Our aim is not simply to file everything on the deadline.

We want our clients to know what is due, when it is due and roughly what they should expect to pay, so there are fewer surprises.

If you would like help getting your business finances organised and making sure important deadlines are not missed, please get in touch with Partridge Accountancy Services.

Running a small business means juggling customers, suppliers, staff, cash flow and everything else that comes with being your own boss.

Unfortunately, HMRC deadlines do not disappear just because you are busy.

Missing a tax or filing deadline can lead to penalties, interest and unnecessary stress, so knowing the key dates in advance is one of the simplest ways to keep your business finances under control.

Here are some of the main tax deadlines UK small business owners should be aware of.

Self Assessment – 31 January

For sole traders, landlords, company directors and others who need to complete a Self Assessment tax return, 31 January is one of the most important dates in the tax calendar.

For the 2025/26 tax year, the deadline for filing your online Self Assessment tax return is:

31 January 2027

This is also normally the deadline for paying:

• any Income Tax and National Insurance due for 2025/26; (and, in some cases)
• your first payment on account towards the 2026/27 tax year, where applicable.

NOTE: If you are filing a paper tax return, the deadline is earlier: 31 October 2026.

Don't leave your tax return until January

Although the deadline is in January, you can prepare your tax return as soon as the tax year ends on 5 April.

Completing it earlier gives you more time to:

• understand how much tax you owe
• plan your cash flow
• check whether anything is missing
• avoid the January rush

NOTE: Submitting your tax return early does not mean you have to pay the tax early.

Payments on Account – 31 January and 31 July

If you are self-employed and your tax bill meets the relevant criteria, HMRC may ask you to make payments on account towards your next tax bill.

These are normally paid in two instalments:

31 January

and

31 July

This often catches new business owners by surprise.

For example, your January bill could include both the outstanding tax for the previous year and an advance payment towards the next year.

Good tax planning can help make sure this does not come as an unpleasant surprise.

Making Tax Digital for Income Tax – Quarterly Deadlines

Making Tax Digital for Income Tax became mandatory from 6 April 2026 for qualifying sole traders and landlords with relevant qualifying income over £50,000.

Instead of only dealing with HMRC once a year, those within MTD must maintain digital accounting records and send quarterly updates using compatible software.

The standard quarterly deadlines are:

• 7 August
• 7 November
• 7 February
• 7 May

For the 2026/27 tax year, the first quarterly deadline was 7 August 2026, and will be followed by 7 November 2026,

7 February 2027 and 7 May 2027.

The quarterly updates do not replace your annual tax return. You will still need to complete your year-end tax submission.

HMRC has confirmed that penalty points will not be issued for late quarterly MTD updates during the 2026/27 tax year, although the updates still need to be submitted before the annual tax return can be completed.

VAT Returns – Usually Every Three Months

If your business is VAT registered, you will usually submit a VAT return every three months.

The deadline is generally:

One month and seven days after the end of the VAT period.

For example, if your VAT quarter ends on 31 March, your VAT return and payment would normally be due by 7 May.

VAT deadlines will vary depending on the VAT quarters allocated to your business, so it is important to check your own VAT schedule rather than relying on another business's dates.

NOTE: Keeping your bookkeeping up to date throughout the quarter makes preparing your VAT return much easier.

PAYE and Payroll Deadlines

If you employ staff, payroll brings its own set of regular deadlines.

Your Full Payment Submission (FPS) should normally be sent to HMRC on or before the date you pay your employees.

PAYE and National Insurance collected through payroll is then usually payable to HMRC by the:

22nd of the following month if paying electronically.

For businesses that qualify to pay PAYE quarterly, different payment dates can apply.

Payroll errors can affect not only your business but also your employees' tax records, pensions and benefits, so this is one area where being organised is particularly important.

Corporation Tax Payment – 9 Months and 1 Day

Limited companies have different deadlines from sole traders.

For most small companies, Corporation Tax must be paid:

9 months and 1 day after the end of the Corporation Tax accounting period.

For example, if your company's year end is:

31 March 2026

the Corporation Tax payment deadline would normally be:

1 January 2027

NOTE: An important point to remember is that the tax is normally due before the Corporation Tax return itself has to be filed.

Corporation Tax Return – 12 Months

Your company's Corporation Tax Return must usually be submitted to HMRC:

12 months after the end of the accounting period.

So, using the same company with a 31 March 2026 year end, the Corporation Tax Return would normally need to be filed by:

31 March 2027

Even if your company has made a loss or has no Corporation Tax to pay, you may still be required to file a Company Tax Return if HMRC has issued a notice requiring one.

Companies House Accounts – Usually 9 Months

Limited companies also need to file annual accounts with Companies House.

For most private limited companies, the deadline is:

9 months after the company's financial year end.

For example:

Company year end: 31 March 2026

Companies House filing deadline: 31 December 2026

Different rules apply to a company's first set of accounts. A private company's first accounts are generally due 21 months after incorporation, although the exact deadline depends on the accounting period.

Confirmation Statement – Every Year

Every UK limited company must also submit a Confirmation Statement to Companies House.

This confirms important company information such as:

• registered office
• directors
• shareholders
• people with significant control
• share capital
• certain other business information

NOTE: Your Confirmation Statement date is specific to your company, so this is not one universal annual deadline.

It is important not to confuse the Confirmation Statement with your annual accounts. They are separate filing obligations.

Your Company's Deadlines May Be Different

One of the reasons business deadlines can become confusing is that not every business follows exactly the same calendar.

Your deadlines may depend on:

• whether you are a sole trader or limited company
• your company's financial year end
• your VAT quarters
• whether you operate payroll
• whether you fall within Making Tax Digital
• personal Self Assessment circumstances

This is why simply copying dates from another business owner is rarely a good idea.

Missing a Deadline Can Cost You

Leaving things until the last minute can result in:

• late filing penalties
• late payment penalties
• interest
• Companies House penalties
• HMRC correspondence
• cash-flow problems
• unnecessary stress

More importantly, repeatedly preparing your accounts at the last minute makes it difficult to use the financial information to actually manage your business.

Your accounts should tell you what is happening in your business — not simply become something you deal with when HMRC asks for them.

A Simple Way to Stay Ahead

A good routine is to keep your bookkeeping updated throughout the year rather than trying to reconstruct everything just before a deadline.

Ideally:

• reconcile your bank regularly
• upload receipts as you receive them
• review outstanding invoices
• keep payroll information up to date
• set money aside for tax
• peak to your accountant before making major financial decisions

NOTE: The earlier we have accurate information, the more opportunity there is to identify problems and consider tax-planning opportunities.

Need Help Keeping Track of Your Business Deadlines?

At Partridge Accountancy Services, we help sole traders and limited companies stay on top of their accounts, VAT, payroll, Corporation Tax, Self Assessment and Making Tax Digital obligations.

Our aim is not simply to file everything on the deadline.

We want our clients to know what is due, when it is due and roughly what they should expect to pay, so there are fewer surprises.

If you would like help getting your business finances organised and making sure important deadlines are not missed, please get in touch with Partridge Accountancy Services.

Partridge Accountancy Services
Helping businesses stay informed, compliant and prepared.

Simple.