What Happens If You Miss a Corporation Tax Deadline?

15 September 2025

For limited companies, paying Corporation Tax on time is a legal requirement—and missing a deadline can quickly become expensive. At Evans Entwistle, we work with clients across the UK to make sure this doesn’t happen.

When is Corporation Tax due?

Corporation Tax payments are usually due nine months and one day after the end of your accounting period. For example, if your company’s year-end is 31 December, you’ll need to pay by 1 October the following year.

Your Corporation Tax return (form CT600) has a different deadline: it must be filed within 12 months of the end of your accounting period. Because the payment deadline falls before the filing deadline, many businesses are caught out if they haven’t planned ahead.

What if you miss the deadline?

If payment isn’t made on time, HMRC will charge interest from the very next day until the liability is settled. Late filing of the CT600 also triggers automatic penalties, starting with a fine for being just one day overdue. These penalties increase the longer the return is outstanding and can damage your company’s compliance record.

How Evans Entwistle can help

We know that running a business leaves little time to keep on top of tax dates. That’s why we provide proactive reminders, accurate tax forecasting, and hands-on support to ensure deadlines are never missed. Our team can also identify allowances and reliefs to help reduce your overall Corporation Tax bill.

With Evans Entwistle managing your tax compliance, you can focus on running your business while we handle the deadlines, paperwork, and peace of mind.