Corporation tax payment deadlines: A complete calendar

Published Tuesday 22 September 2026

Table of contents

• What is the corporation tax deadline?
• When is your corporation tax payment due?
• When is your Company Tax Return filing deadline?
• Corporation tax deadlines for larger companies
• Corporation tax deadlines in your first year
• What happens if you miss the corporation tax deadline?
• How to pay your corporation tax on time
• Stay on top of corporation tax deadlines with Xero
• FAQs on corporation tax deadlines

Key takeaways

• Corporation tax is usually due nine months and one day after your accounting period ends, while your Company Tax Return is due 12 months after it, so you pay before you file.
• Your exact deadlines depend on your company's year-end, so no two businesses have the same dates.
• Companies with profits over £1.5 million pay in quarterly instalments instead of one payment.
• Missing a deadline brings penalties from £200 plus interest on unpaid tax, so it helps to set reminders early.

What is the corporation tax deadline?

If you run a limited company, the corporation tax deadline is really two separate dates, and it's easy to mix them up. There's the deadline to pay your bill, and the deadline to file your Company Tax Return.

Both dates are tied to your accounting period, which is normally the 12 months your annual accounts cover. The payment deadline comes first and the filing deadline comes later, so you often pay your tax before you send in the return that shows how much it is. If you'd like a refresher on how corporation tax is worked out, reviewing this guide can help before you plan your dates.

The process can feel back-to-front the first time you do it, but it makes sense once you see the two jobs as separate. Paying is about getting money to His Majesty’s Revenue and Customs (HMRC) on time. Filing is about telling HMRC how you arrived at the figure. The rest of this guide walks through each date in turn, with worked examples for common year-ends, so you can pin down the exact deadlines that apply to your own company.

When is your corporation tax payment due?

Corporation tax is usually due nine months and one day after the end of your accounting period. This applies to companies with taxable profits of up to £1.5 million, which covers the vast majority of small businesses.

Your accounting period is the time your annual accounts cover, usually 12 months, so your corporation tax due date depends entirely on your year-end. You can confirm your own payment date on the GOV.UK guide to paying your corporation tax bill.

How to work out your corporation tax due date

To find your date, take the last day of your accounting period and add nine months and one day. Two common year-ends show how it works:

• Year-end of 31 March: Payment is due by 1 January the following year.
• Year-end of 31 December: Payment is due by 1 October the following year.

If the deadline lands on a weekend or bank holiday, make sure your payment reaches HMRC by the last working day before, unless you're paying by Faster Payments. It's the date the money arrives that counts, not the date you press send, so slower methods need a few days' head start. If your year-end shifts, your payment date shifts with it, so it's worth working out your date fresh each year rather than assuming it stays the same.

When is your Company Tax Return filing deadline?

Your Company Tax Return, known as the CT600, is due 12 months after the end of your accounting period. That's three months later than the payment deadline, which is why you usually pay first and file second.

Keep one thing separate in your mind: your annual accounts for Companies House have their own deadline, normally nine months after your financial year-end. Filing accounts with Companies House and filing your return with HMRC are two different jobs.

Because these deadlines fall on different dates and go to different places, plenty of directors track them side by side in one calendar. Your return also needs to match the accounts you file, so it pays to get your figures straight before either deadline arrives rather than rushing both at once.

Corporation tax deadlines for larger companies

If your company's profits are higher, you pay corporation tax in instalments rather than one lump sum. The rules split into two bands:

• Profits between £1.5 million and £20 million: Pay in four quarterly instalments.
• Profits over £20 million: Pay on an earlier instalment schedule.

Most small businesses won't reach these thresholds, but it's worth knowing the point at which the rules change. The thresholds are also shared across companies in the same group, so if your business grows or joins a group, keep an eye on where your profits sit. Once you're paying by instalments, you're settling part of the bill during the accounting period rather than after it, which is a very different rhythm from a single annual payment.

Corporation tax deadlines in your first year

Your first year has a few quirks that catch new directors out. You need to register for corporation tax within three months of starting to do business, which includes buying, selling, advertising, or employing someone. Registering on time matters, because your deadlines are calculated from your accounting period whether or not you've told HMRC you're trading.

Your first set of accounts often covers more than 12 months. Because an accounting period for corporation tax can't be longer than 12 months, HMRC splits that first stretch into two accounting periods. That means two returns and two payment dates in your first year, so it's worth checking both dates early.

The split usually gives you one period of 12 months and a shorter period covering the remaining days. Each period then has its own payment date nine months and one day after it ends, and its own filing date. It sounds fiddly, but once you've noted all four dates in your calendar, your first year runs much like any other.

What happens if you miss the corporation tax deadline?

Filing late triggers automatic penalties from HMRC, even if you have no tax to pay. The current penalties for a late Company Tax Return are:

• £200: as soon as your return is one day late
• A further £200: once it's three months late
• 10% of your unpaid tax: once you're six months late, based on HMRC's estimate of your bill
• A further 10% of any unpaid tax: once you're 12 months late

If your return is late three times in a row, the £200 penalties rise to £1,000 each. Paying late is charged separately, so HMRC adds interest to unpaid corporation tax at 7.75% (the late payment rate from 9 January 2026), and the longer you leave it, the more it costs. You can check the full schedule on the GOV.UK guide to penalties for late filing.

How to pay your corporation tax on time

Staying on time is mostly about knowing your dates and setting money aside throughout the year. Follow these steps:

1. Note your payment date (nine months and one day after your year-end) and your filing date (12 months after).
2. Set a reminder a few weeks before each date so you have time to act.
3. Put money aside regularly so the bill doesn't land as a surprise.
4. Keep your bookkeeping up to date so you know your profit and roughly what you'll owe.
5. Pay early where you can, and allow time for the payment method to clear.

Payments by online or telephone banking, or by debit or corporate credit card, usually reach HMRC quickly, while other methods can take several working days. If you're paying close to the deadline, choose a faster method and check when the money will actually land.

Keeping your bookkeeping up to date also keeps you ready for Making Tax Digital (MTD), HMRC's move to digital record-keeping. When your records are current all year, working out your bill becomes a quick check rather than a scramble, and you can set money aside with confidence long before the date arrives.

Stay on top of corporation tax deadlines with Xero

Managing deadlines is far easier when your numbers are current and in one place. Online accounting software keeps your income and expenses up to date, gives you a real-time view so you can forecast your cash flow, and helps you set money aside for tax before it's due.

Ready to take the stress out of tax season? Get one month free.

FAQs on corporation tax deadlines

Here are quick answers to the questions business owners ask most about corporation tax deadlines.

When is corporation tax due for a limited company?

For most companies, corporation tax is due nine months and one day after the end of your accounting period. Companies with profits over £1.5 million pay in quarterly instalments instead.

Can you pay corporation tax late?

You can, but HMRC charges daily interest on the unpaid amount from the day after it was due. Filing your return late also brings separate penalties.

What is the deadline for filing a Company Tax Return?

Your Company Tax Return is due 12 months after the end of your accounting period. Note, this is later than the payment deadline.

Do you pay corporation tax before or after filing your return?

You usually pay first. The payment deadline falls three months before the filing deadline, so payment comes well before you send in your return.