Key UK Business Accounting Dates for August 2025

Stay on top of your accounting with this guide to key UK tax and filing deadlines in August 2025. Avoid penalties with this checklist for businesses and the self-employed.

August might feel like a quiet month for many UK businesses, but it still comes with important tax and accounting deadlines you can’t afford to miss. From PAYE submissions to VAT returns and CIS payments, staying organised will help you avoid penalties and keep your business running smoothly. Here’s a clear guide to the key UK accounting dates for August 2025, plus who they apply to and what you need to do.

01/08/2025 – Corporation Tax payment: 31 October 2024 year ends

If your company’s accounting year ended on 31 October 2024, your Corporation Tax payment is due by 1 August 2025.

Limited companies in the UK must pay their Corporation Tax 9 months and 1 day after the end of their accounting period. Missing this deadline can lead to interest charges and possible penalties from HMRC.

Tip: Make sure you’ve also filed your Company Tax Return (CT600) before the filing deadline (which is normally 12 months after your year end). Keep records of your payment confirmation for your accounts and future HMRC checks.

Useful link: Pay your Corporation Tax bill – GOV.UK

02/08/2025 – P46(car) electronic or paper: quarter to 5 July 2025

If you provide company cars to your employees or directors, you must submit a P46(Car) form to HMRC each quarter. For the quarter ending 5 July 2025, the submission deadline for electronic or paper returns is 2 August 2025.

The P46(Car) notifies HMRC about any new company cars provided, cars withdrawn, or car changes for employees. This ensures employees are taxed correctly on the Benefit in Kind (BIK) value.

Tip: File your P46(Car) electronically through your payroll software or HMRC’s online services to avoid postal delays and keep your PAYE records up to date.

Useful link: Company car tax forms – GOV.UK

03/08/2025 – Employment intermediaries: report for the quarter to 5 July 2025

If your business supplies workers to clients through an agency or intermediary, you may need to submit an Employment Intermediaries report to HMRC every quarter. For the quarter ending 5 July 2025, the deadline to file this report is 3 August 2025.

This report provides HMRC with details of workers you place with clients where PAYE wasn’t operated, helping HMRC track off-payroll working arrangements and ensure tax compliance.

Tip: Make sure your records include worker names, dates, fees paid, and National Insurance numbers. You can file your report through HMRC’s online Employment Intermediaries Service.

Useful link: Employment Intermediaries – GOV.UK

04/08/2025 – Employment intermediaries: remove a report for the quarter to 5 April 2025

If you filed an Employment Intermediaries report for the quarter ending 5 April 2025 and later realise it was submitted in error (for example, you had no reportable workers that quarter), you must formally remove it with HMRC by 4 August 2025.

Failing to remove an incorrect report could lead to unnecessary follow-ups from HMRC or potential compliance issues.

Tip: Use HMRC’s online Employment Intermediaries portal to remove the report or contact HMRC if you need help correcting it.

Useful link: Employment Intermediaries – GOV.UK

07/08/2025 – VAT return payment: month or quarter-end 30 June 2025

If your business is VAT registered, and your VAT accounting period ended on 30 June 2025 (monthly or quarterly), then your VAT return and payment are both due by 7 August 2025.

You must submit your VAT return online through your Making Tax Digital (MTD)-compliant software and ensure that the payment reaches HMRC by this date to avoid late payment interest and possible penalties.

Tip: Allow extra time for your bank’s processing times and remember weekends and bank holidays may delay payments clearing.

Useful link: Submit your VAT Return – GOV.UK