The 1 July 2026 Tax Deadline Every Company Director Should Know About

 

The end of June marks an important deadline for many UK limited companies. If your company's accounting period ended on 30 September 2025, the deadline for paying your Corporation Tax liability is 1 July 2026. 

 

While many business owners focus on preparing and filing their annual accounts and Company Tax Return, it is important to remember that Corporation Tax is usually payable long before the filing deadline arrives. Failing to make payment on time can result in interest charges from HMRC and create unnecessary financial pressure for your business. 

 

In this article, we'll explain what the deadline means, how Corporation Tax payment dates are calculated, what happens if you miss the deadline, and the steps you can take to ensure your business remains compliant. 

 

 

For most UK limited companies, Corporation Tax must be paid nine months and one day after the end of the accounting period. 

 

For example: 

 

 

This distinction is important because many directors mistakenly assume they have until the CT600 filing deadline to pay their Corporation Tax bill. In reality, HMRC expects payment significantly earlier. 

 

The Company Tax Return confirms the final tax position, but the tax itself must usually be paid before the return is submitted. 

 

 

Corporation Tax is the tax UK limited companies pay on their taxable profits. These profits can include: 

 

 

The amount due will depend on the company's taxable profits after accounting for allowable business expenses, capital allowances, losses brought forward, and any available reliefs. 

 

Accurate bookkeeping throughout the year can help ensure that tax liabilities are calculated correctly and that businesses are not caught off guard when payment deadlines approach. 

 

 

Many businesses face cash flow challenges when large tax bills become due. Waiting until the last minute to calculate your Corporation Tax liability can leave little time to make financial arrangements. 

 

By reviewing management accounts regularly and forecasting profits throughout the year, directors can gain a clearer picture of their likely tax obligations and set aside funds accordingly. 

 

Businesses that proactively budget for Corporation Tax often find it easier to manage cash flow and avoid unexpected financial strain. 

 

 

Missing a Corporation Tax payment deadline can prove costly. 

 

HMRC will charge interest on any outstanding balance from the day after the payment was due. The interest continues to accrue until the liability is settled in full. 

 

Although Corporation Tax does not attract automatic fixed penalties for late payment in the same way as some other taxes, the interest charges can become significant, particularly for larger liabilities or extended periods of non-payment. 

 

Repeated compliance issues may also increase the likelihood of HMRC enquiries or additional scrutiny of a company's tax affairs. 

 

For this reason, businesses should ensure that payment reaches HMRC by the deadline rather than simply initiating payment on the due date. 

 

 

HMRC offers several payment methods, including: 

 

 

One of the most common and convenient methods. Payments are usually received quickly, particularly when using Faster Payments. 

 

 

Many UK banks support Faster Payments, allowing businesses to transfer funds directly to HMRC, often on the same day. 

 

 

For larger payments, CHAPS offers a secure same-day transfer option, although banks may charge a fee. 

 

 

Some companies may choose to pay via Direct Debit, although this requires sufficient notice and setup time. 

 

 

HMRC accepts certain card payments, providing another option for businesses needing flexibility. 

 

Whichever payment method is chosen, directors should allow sufficient time for the payment to clear before the deadline. 

 

 

While the standard rule applies to most small and medium-sized businesses, larger companies may be subject to different payment arrangements. 

 

Companies with taxable profits above certain thresholds may need to pay Corporation Tax through quarterly instalments during the accounting period rather than making a single payment after the year end. 

 

These rules can become complex, particularly for companies within groups, so professional advice may be beneficial where profits approach or exceed the relevant thresholds. 

 

 

As the payment deadline approaches, there are several common errors that businesses should be aware of: 

 

 

One of the most frequent misunderstandings is confusing the CT600 submission deadline with the tax payment deadline. 

 

 

Businesses often delay calculating Corporation Tax until final accounts are completed. However, estimating liabilities in advance can help avoid cash flow surprises. 

 

 

Incorrect payment references can delay HMRC allocating funds to the correct account, potentially leading to avoidable complications. 

 

 

Bank processing times vary, and delays can occur. Making payment several days before the deadline reduces the risk of late payment interest. 

 

 

With the deadline approaching, now is a good time to: 

 

 

Taking these steps can help ensure compliance while providing greater certainty over your business finances. 

 

 

For companies with a 30 September 2025 accounting period end, the 1 July 2026 Corporation Tax payment deadline is fast approaching. 

 

Although the Company Tax Return does not need to be submitted until 30 September 2026, the tax itself must be paid three months earlier. Taking the time to review your financial position, estimate your liability, and ensure funds are available can help you avoid unnecessary interest charges and stay compliant with HMRC requirements. 

 

At JSB Accountants, we work closely with businesses to help them understand their tax obligations, plan ahead for key deadlines, and maximise available tax reliefs. If you're unsure how much Corporation Tax is due or would like support with your year-end accounts and tax planning, our experienced team is here to help. Get in touch with JSB Accountants today to ensure your Corporation Tax affairs are in order before the deadline arrives.