Key Accounting Dates for UK Businesses in March 2025

/Published:25th February 2025/inBusiness, Tax

key accounting dates for UK businesses in March 2025 - accounting wise

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March is a crucial month for UK businesses when it comes to accounting and tax deadlines. With the end of the financial year approaching, it’s essential to stay on top of key dates to avoid penalties and ensure compliance with HMRC. From VAT return deadlines to corporation tax payments and payroll submissions, missing an important deadline could lead to unnecessary fines and cash flow issues. In this guide, we’ll outline the key accounting dates for UK businesses in March 2025, helping you plan ahead and keep your finances in order.

01/03/2025 – Corporation Tax payment: 31 May 2024 year ends

If your company’s financial year ended on 31 May 2024, your Corporation Tax payment is due by 31 March 2025. UK companies typically have nine months and one day from the end of their accounting period to settle their Corporation Tax bill with HMRC. Missing this deadline could result in interest charges and potential penalties, so it’s crucial to ensure your payment is processed on time. You can pay your Corporation Tax via online banking, direct debit, or debit/credit card, but keep in mind that some payment methods take longer to clear. Planning ahead and ensuring you have sufficient funds available will help you avoid last-minute stress and compliance issues.

01/03/2025 – Advisory fuel rates for company car drivers: new rates published

On 1 March 2025, HMRC will publish the latest Advisory Fuel Rates (AFRs) for company car drivers. These rates are updated quarterly and are used to calculate fuel reimbursement costs for employees using company vehicles. Employers can use AFRs to reimburse staff for business mileage or to determine the amount employees should repay for private fuel use. The rates vary depending on the fuel type and engine size of the vehicle, so it’s important for businesses to check the latest figures to ensure accurate reimbursements and avoid tax complications. Keeping up to date with these changes helps businesses maintain compliance and manage company car expenses efficiently.

07/03/2025 – VAT return submission and payment (online): month-end or quarter 31 January 2025

Businesses that file VAT returns on a monthly or quarterly basis and have an accounting period ending on 31 January 2025 must submit their return and make payment by 7 March 2025. This applies to VAT-registered businesses using the Making Tax Digital (MTD) for VAT system, meaning returns must be filed online through compatible software. Missing this deadline could result in late payment interest and penalties from HMRC. To avoid last-minute issues, ensure that your VAT records are up to date, your submission is accurate, and your payment method allows for timely processing. Planning ahead can help you stay compliant and maintain smooth cash flow management.

19/03/2025 – PAYE, NIC and CIS payment (postal): month-end 5 March 2025

For businesses that process payroll, the deadline for postal payments of PAYE, National Insurance Contributions (NIC), and Construction Industry Scheme (CIS) deductions for the period ending 5 March 2025 is 19 March 2025. This applies to employers who still use postal methods such as cheques to pay HMRC. It’s important to allow enough time for your payment to reach HMRC before the deadline to avoid interest charges or late payment penalties. However, if you prefer to pay electronically, you have a few extra days, with the deadline extending to 22 March 2025. To ensure compliance, consider switching to online payments, which are faster, more secure, and provide instant confirmation.

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19/03/2025 – CIS return: payments made to subcontractors in the month to 5 March 2025

If your business is registered under the Construction Industry Scheme (CIS) and you’ve made payments to subcontractors between 6 February and 5 March 2025, you must submit your CIS return by 19 March 2025. This return details the payments made and any deductions taken for tax purposes. Even if no payments were made during this period, you must still file a nil return to avoid penalties. Failure to submit on time could result in automatic fines from HMRC, starting at £100 for being just one day late. To stay compliant, ensure that all subcontractor records are accurate and submit your return well before the deadline.

22/03/2025 – PAYE, NIC and CIS payment (electronic): month-end 5 March 2025

For businesses making electronic payments of PAYE, National Insurance Contributions (NIC), and Construction Industry Scheme (CIS) deductions for the period ending 5 March 2025, the deadline is 22 March 2025. This extended deadline applies only to payments made via online banking, direct debit, or other electronic methods. Ensuring your payment reaches HMRC on time is crucial to avoid interest charges or penalties. Since some payment methods take longer to process, it’s best to initiate transactions a few days in advance. Using electronic payments is not only faster and more secure but also provides instant confirmation of receipt, helping businesses maintain compliance with HMRC requirements.

26/03/25 – Spring Forecast

On 26 March 2025, the UK government will release its Spring Forecast, which typically includes important updates on economic projections, fiscal policy, and potential changes to tax regulations. This annual event can significantly impact businesses and their financial planning, as it may introduce new measures aimed at stimulating growth or addressing economic challenges. Staying informed about these developments is crucial for business owners, as the forecasts can influence investment decisions, budget allocations, and overall strategic planning. It’s advisable to review the Spring Forecast closely and consider how any proposed changes may affect your business operations and financial strategy moving forward.

31/03/2025 – Corporation Tax returns: 31 March 2024 year ends

Companies with a financial year ending on 31 March 2024 must file their Corporation Tax return (CT600) by 31 March 2025. UK companies are required to submit their return to HMRC within 12 months of their accounting period end, detailing their taxable profits and any Corporation Tax owed. Even if no tax is due, the return must still be filed to avoid penalties. Late submissions can result in automatic fines, starting at £100 for being just one day late, with further penalties increasing over time. To stay compliant, ensure all financial records are accurate and submit your return well before the deadline, preferably using HMRC-recognized accounting software for a smooth process.

31/03/2025 – Annual Tax on Enveloped Dwellings: amend ATED returns for year to 31 March 2024

Businesses and individuals owning UK residential properties valued over £500,000 through a company or corporate structure must review and amend their Annual Tax on Enveloped Dwellings (ATED) return for the period ending 31 March 2024 by 31 March 2025. This deadline allows property owners to correct any errors or update details in their previously submitted return. If amendments are needed, it’s important to act promptly to avoid potential penalties or interest charges from HMRC. Keeping accurate records of property valuations and tax payments ensures compliance and prevents unexpected tax liabilities. If you’re unsure about your ATED obligations, seeking professional tax advice can help navigate the complexities of this levy.

31/03/2025 – Stamp Duty Land Tax: cuts introduced on 23 September 2022 reversed

As of 31 March 2025, the temporary cuts to Stamp Duty Land Tax (SDLT) introduced on 23 September 2022 will be reversed. This means that property buyers may face higher SDLT rates, which could impact affordability and demand in the housing market. The reversal of these cuts is part of the government’s ongoing efforts to balance the budget and manage public finances amid changing economic conditions. For businesses and individuals planning property transactions, it’s essential to factor in these potential increases when budgeting for property purchases. Staying informed about SDLT changes can help you make more strategic decisions and avoid unexpected costs in the property market.

31/03/2025 – Capital Allowances: 100% First Year Allowance for zero-emissions goods vehicles due to end for Corporation Tax purposes

The 100% First Year Allowance for zero-emissions goods vehicles will come to an end on 31 March 2025 for Corporation Tax purposes. This incentive has encouraged businesses to invest in environmentally friendly vehicles, allowing them to deduct the full cost of qualifying zero-emission vehicles from their taxable profits in the year of purchase. After this deadline, companies will need to revert to standard capital allowance rates, which may reduce the immediate tax benefits associated with purchasing new vehicles. If your business is considering investing in zero-emission goods vehicles, it’s crucial to act before this deadline to maximize your tax relief. Assess your fleet needs and consult with a tax advisor to ensure you take full advantage of this opportunity before it expires.

Conclusion: Stay Compliant and Focus on Growth

Staying on top of key accounting deadlines is essential for keeping your business compliant and avoiding unnecessary penalties. March 2025 brings several important dates for Corporation Tax, VAT, PAYE, CIS, and ATED, so planning ahead is crucial. By ensuring your returns are submitted and payments are made on time, you can maintain good financial health and focus on growing your business.

If you need support with your accounting or tax obligations, Accounting Wise is here to help—get in touch with our expert team for guidance and hassle-free compliance.

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Accounting Wise is a trading style of Accounting Wise Ltd, a limited company registered in England under company number 09365202. Our registered office is: The Carriages, Station Road, Ware, SG12 9PL UK.

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