Key accounting deadlines for small businesses

Staying on top of HMRC deadlines can feel overwhelming — VAT, tax returns, CIS, year-end accounts… the list goes on.

The good news? At Books & Business, we keep track of these dates for you, so you’ll never miss a deadline or face a penalty.

Here’s a quick guide to the most important deadlines every small business owner should know.

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VAT return deadlines

  • Quarterly VAT returns must usually be submitted 1 month + 7 days after the end of your VAT period. 
  • Example: If your VAT period ends 31sth March, your return is due by the 7th May

We will remind you each month to send in paperwork, so your VAT return is always filled on time.

Making Tax Digital (MTD)for VAT &  Income Tax

  • MTD for VAT is already mandatory for most VAT-registered businesses.
  • MTD for Income Tax Self Assessment (ITSA) will apply from April 2026 to many sole traders and landlords.
  • This means quarterly digital updates instead of one bing annual return.

We can assist you in making sure you are fully set up and ready for MTD well before the deadline.

Self Assessment deadlines

  • Paper returns: 31st October (following the end of the tax year)
  • Online tax returns: 31st January
  • Tax payments: also due by 31st January (plus 31st July for payments on account)

We'll prepare and file your personal tax return so you never have to worry about missing these key dates

Construction Industry Scheme (CIS) deadlines

  • CIS monthly returns are due by the 19th of the following month.
  • Payments must also be made by this date

We can prepare and submit your CIS returns, making sure contractors and subcontractors stay compliant.

Year-End Accounts & Corporation Tax

  • Limited companies must file accounts with Companies House 9 months after year-end
  • Corporation tax must usually be paid within 9 months and 1 day of the year-end

We'll keep you on track with reminders and ensure everything is submitted on time.

The Easy Way to Never Miss a Deadline

Deadlines are important - but they don't have to keep you awake at night.  At Books & Business, we:


  • Chase paperwork monthly (not quarterly)
  • File VAT, and tax returns on time
  • Keep you prepared for MTD ITSA in 2026
  • Give you peace of mind that everything is under control


Book your free discovery call today and let us take deadlines off your to-do list.


Book your free discovery call


Please note: While we take every step to ensure your returns and submissions are filed on time, this relies on clients providing the necessary information and paperwork promptly.  Books & Business cannot accept any responsibility for missed deadlines cause by delays in receiving information from clients.