The two dates, in the order they happen
- Payment: 9 months and 1 day after the accounting period ends.
- Filing the CT600: 12 months after the accounting period ends.
So for a 31 March year end, the tax is due by 1 January and the return by 31 March. The company is expected to know the number and pay it three months before it files.
For 2026/27, companies with profits above £1.5m usually pay quarterly instalments instead. The limit is shared between associated companies, and there is an exception for the first year a company crosses it.
How to pay it
Online or telephone banking is quickest and same-day. Use HMRC’s Cumbernauld account details, or Shipley if the payslip says so. Faster Payments, CHAPS and Bacs all work, with Bacs taking three working days.
Direct Debit is available but needs setting up well in advance the first time. The company can also pay by corporate debit or credit card, and HMRC charges a fee on both.
The reference is the bit that goes wrong. It is the 17-character Corporation Tax payslip reference, not the UTR on its own, and it changes every accounting period. Using last year’s reference sends the money to the wrong period and produces a demand for tax already paid.
The rates for 2026/27
For 2026/27 the rate is 19% on profits up to £50,000 and 25% on profits above £250,000. Marginal relief applies in between, which for 2026/27 produces an effective rate of 26.5% on the slice from £50,000 to £250,000.
Both limits are divided by the number of associated companies plus one, so having a second company can push the first into a higher rate.
If the company is late, or cannot pay
Late payment interest runs from the day after the due date, charged at the Bank of England base rate plus a margin. Unlike penalties, interest on late-paid Corporation Tax is deductible for the company, and any repayment interest HMRC pays is taxable.
If the company cannot pay, contact HMRC before the deadline and ask about a Time to Pay arrangement. Asking in advance is treated differently from being chased afterwards.
Filing late triggers penalties; paying late runs up interest. They are two different things, and it is possible to do both.
Common questions
Q1When is Corporation Tax due?
Nine months and one day after the accounting period ends. The return itself is not due until twelve months after.
Q2What reference do I use?
The 17-character Corporation Tax payslip reference for that accounting period. It changes each period, and using an old one misallocates the payment.
Q3Can I pay in instalments?
Usually only if profits exceed £1.5m for 2026/27, when quarterly instalments apply; the limit is divided between associated companies, and the first year over it is normally exempt. Otherwise it is one payment, though Time to Pay may be available if the company cannot meet it.
Q4What if I file late but pay on time?
The company still gets late filing penalties. Filing and payment are separate obligations: penalties for one, interest on the other.
