For many limited companies, the end of the calendar year feels like the natural time to wrap things up, but once the Christmas decorations are all packed away and January gets underway, there are still important tax deadlines to think about. If your company’s accounting period ended on 31st December 2025, your Corporation Tax payment deadline is 30th September 2026.
That might sound like plenty of time, but September has a habit of arriving much quicker than expected. Especially when you’re busy running a business, managing staff, dealing with customers and trying to get back into a routine after the summer.
When Is My Corporation Tax Due?
For most companies with taxable profits of up to £1.5 million, Corporation Tax is normally due nine months after the end of the accounting period. For a company with a 31st December 2025 year end, that makes the payment deadline 30th September 2026.
It’s worth remembering that paying your tax and filing your Company Tax Return are two separate deadlines. The return is generally due 12 months after the end of the accounting period, meaning you shouldn’t assume that having more time to file means you have more time to pay.
What Does My Company Need To Do?
Before the September deadline arrives, you’ll need to know how much Corporation Tax your company owes and make sure the payment reaches HMRC on time.
This means getting your accounts and financial records in order, checking income and allowable expenses, and making sure any relevant tax reliefs or allowances have been considered. Your taxable profit isn’t necessarily the same as the profit shown in your annual accounts, so simply looking at your business bank balance won’t tell you what your tax bill will be.
This is where good bookkeeping throughout the year really pays off. If you’re trying to piece together receipts, invoices and expenses at the last minute, working out your Corporation Tax liability can become much more stressful than it needs to be.
Don’t Forget About Cash Flow
Knowing that you owe Corporation Tax is one thing. Having the money available to pay it is another.
It’s surprisingly easy for a profitable company to feel short on cash. Perhaps you’ve invested in new equipment, taken on another member of staff, paid suppliers or simply reinvested money back into the business. The tax bill doesn’t disappear just because the money has been put to good use elsewhere.
Planning ahead can make a significant difference. If you have an idea of your expected tax liability well before 30th September, you can build the payment into your cash-flow planning rather than scrambling to find the money when the deadline is approaching.
What Happens If I Miss The Deadline?
Missing a Corporation Tax payment deadline can lead to interest being charged by HMRC, whilst late filing of the Company Tax Return can result in penalties. Importantly, these are separate obligations, so getting one right doesn’t automatically mean the other has been dealt with.
It’s also worth remembering that late payment interest can build up from the day after the tax was due until the payment is made. So, if you know your company may struggle to meet the Corporation Tax bill on time, it’s much better to speak to your accountant as early as possible rather than waiting for HMRC to get in touch. A little forward planning can help you understand your options and avoid an already stressful situation becoming more expensive.
How Accounts & Returns Can Help
Keeping on top of Corporation Tax isn’t simply about meeting a deadline. It’s about understanding what your company owes, planning for the payment and making sure your accounts are prepared properly.
At Accounts & Returns, we can help with your company accounts, Corporation Tax calculations, tax returns and ongoing financial advice, giving you a clearer picture of where your business stands.
If your accounting period ended on 31st December 2025, don’t leave your 30th September 2026 Corporation Tax deadline until the last minute.
Whether you’re unsure what you owe, need help getting your records in order or simply want some reassurance that everything has been dealt with correctly, get in touch with your local branch today.
