Beating the deadlines: tax dates for business owners

Tax deadlines can be easy to overlook when you're focused on running a business. But missing one can result in penalties, added costs and unnecessary admin. Being proactive and staying ahead of tax dates can help you stay in control, avoid penalties and focus on running your business.

We take a look at what is coming up:

Self-assessment

Earlier this year up to one million self-assessment taxpayers, which includes sole traders, the self-employed, landlords and many higher and additional rate taxpayers, missed the 31 January 2026 payment deadline for tax owed for the 2024/25 tax year².

Even if you use an accountant, you're still responsible for meeting tax deadlines and paying on time.

• 5 October: register for self-assessment
• 31 October: paper returns
• 31 January: online returns and tax payment
• 31 July: second payment on account (where applicable)

As above, the deadline for submitting an online tax return and payment of the income tax owed for the 2025/26 tax year is 31 January 2027. A late penalty fee of £100 is applied for missing this.

A daily fee of £10 per day is applied if the tax has still not been paid after three months (up to a maximum charge of £900). If the tax has not been paid after six months, interest at 5% is applied on the outstanding bill, or a £300 flat charge, whichever is greater. After 12 months, another 5% or £300 charge is applied.

Pay-as-you-earn (PAYE) employees who have additional untaxed income for 2025/26 can request to pay the tax owed through PAYE. To do this you need to submit your request to HMRC by 11:59pm on 30 December 2026.

Making Tax Digital

Making Tax Digital (MTD), the new tax system for sole traders and landlords, came into force on 6 April and has brought in new deadlines and filing requirements for thousands of taxpayers.

Sole traders and landlords earning more than £50,000 per tax year must now keep digital records and send quarterly updates to HMRC, using government-approved tax software. The first update covers the first three months of the tax year. The next quarterly deadline for submitting tax information under the MTD is 7 November.

Yet one in three business owners required to use Making Tax Digital still haven’t signed up, according to figures from HMRC. It estimated around 864,000 sole traders, self-employed workers and landlords were required to sign up to MTD in its first phase. However, only 436,000 taxpayers filed their tax information by 7 August (the first quarterly deadline under MTD) and only 570,000 taxpayers have registered³.

HMRC is expected to chase up these taxpayers over the next couple of months to register them.

While no penalties will be issued for missing a quarterly deadline under MTD in the first tax year (2026/27), from April 2027 financial penalties could apply to those who miss filing deadlines, making it more important than ever to stay ahead of key tax dates.

From this point, taxpayers who miss a quarterly tax update will get one penalty point. After receiving four penalty points there is a £200 fine, plus a further £200 penalty for every subsequent quarterly deadline missed⁴.

Claire Trott, Head of Advice at St. James’s Place, says: “If you are required to use Making Tax Digital this tax year it is important to get set up as soon as possible, even though there are no penalties applicable to late filing until 
April 2027. It takes time to get used to new systems and ways of doing things so make sure you are in the flow of things before penalties come into force.”

The earning threshold for MTD will fall to £30,000 from April 2027, and down to £20,000 from April 2028. Around 2.9 million sole traders and landlords are expected to be in the MTD system by 2028⁵.

Partnerships

If your partnership's financial year ends between 1 February and 5 April, and one of the partners is a limited company, you may have different tax return deadlines.

You must submit your partnership tax return within:

• 12 months of the partnership's year end if filing online
• Nine months of the partnership's year end if filing a paper return

Limited companies

Limited companies have different tax deadlines from sole traders, so it’s important to keep track of key dates throughout the year.

You’ll usually need to:

• Pay corporation tax within nine months and one day of your company's year-end.
• File annual accounts with Companies House within nine months of your year-end.
• Submit a company tax return to HMRC within 12 months of your year-end, even if no corporation tax is due.
• Pay PAYE and national insurance if you employ staff, including yourself as a director. Payments are usually due by the 19th of the following month, or the 22nd if paying electronically.
• Report employee benefits and expenses, such as private medical insurance, to HMRC each year if applicable.

Get organised, stay ahead

Tax deadlines can feel overwhelming, especially for newer businesses. But getting organised early can help you avoid unexpected penalties and stay focused on running your business.

Sources

¹HMRC press release. 436,000 sole traders and landlords make their tax digital – 12 August 2026
²HMRC press release. 11.48 million beat the self-assessment deadline – 3 February 2026
³ HMRC press release. 436,000 sole traders and landlords make their tax digital – 12 August 2026
⁴HMRC Guidance. Penalties for Making Tax Digital for income tax – 12 March 2026
⁵HMRC Statistical release. Making Tax Digital for Income Tax business population statistics: commentary – 13 August 2025