The most common way to get corporation tax wrong is not missing the deadline. It is paying on time with last year’s reference number.
Your corporation tax payment reference changes every accounting period. Save HMRC as a payee in your business banking app, reuse the reference next year, and the money lands against the wrong period or in a suspense account. The current period shows unpaid. Interest starts running at 7.75%. HMRC begins chasing you for tax you have already paid.
Here is how the reference works, how to find the right one, and every way you are allowed to pay.
The 17-character reference
Your corporation tax payment reference looks like this:
1234567890A00101A
GOV.UK confirms three things about it: the reference is 17 characters, it is specific to one accounting period, and it changes every period. How those 17 characters are put together is not set out in published guidance — the breakdown below comes from HMRC’s internal COTAX manual. On that basis the reference is constructed in four parts:
| Part | Example | What it is |
|---|---|---|
| First 10 digits | 1234567890 |
Your company’s Unique Taxpayer Reference (UTR) |
| Next 4 characters | A001 |
Identifies the charge as corporation tax |
| Next 2 digits | 01 |
The accounting period number — 01 for your first period, 02 for your second, and so on |
| Final character | A |
A fixed suffix |
Only one part changes: the two-digit accounting period number. Which is precisely why the error is so easy to make. 1234567890A00101A and 1234567890A00201A look nearly identical in a banking app, and no system will stop you sending money against the wrong one.
Expect the payment to be misallocated and delayed. GOV.UK’s own warning is blunt: your payment may be delayed if you use the wrong reference number. In practice the money can land against a period that was already settled, leaving a credit on a closed period while the live period accrues interest. Untangling it means contacting HMRC and asking for the payment to be reallocated — which takes time you did not budget for.
Where to find the correct reference
Three reliable sources:
- Your notice to deliver a Company Tax Return — HMRC issues this shortly after each accounting period ends
- Any payment reminder HMRC sends you
- Your company’s HMRC online account, under the relevant accounting period
Check it against the accounting period you are actually paying for, not the one you happen to be sitting in. If you are paying a bill for the year ended 31 March 2026 in December 2026, you need the reference for that period — not the current one.
Penalties use the same reference
If HMRC issues a late filing penalty, pay it with the 17-character reference for the accounting period the penalty relates to. Not a new reference, not the current period’s. Same reference, same bank account.
Every way you can pay
You cannot pay corporation tax by post. Cheques in envelopes are no longer an option.
| Clearing time | Method |
|---|---|
| Same or next day | Approve a payment through your online bank account · Faster Payments · CHAPS · online debit card · online corporate credit card · at your bank or building society |
| 3 working days | Bacs · an existing Direct Debit |
| 5 working days | A first-time Direct Debit |
A few rules that catch people out:
- Personal credit cards are not accepted. A corporate credit card is, but it carries a non-refundable fee. A personal debit card does not.
- Direct Debit cannot be used for payments above £20 million.
- A first-time Direct Debit takes five working days, and it only pulls the amount you tell HMRC to collect. It is not a standing arrangement that guesses your bill.
- Paying at your bank or building society requires a paying-in slip from HMRC, so it is not a same-day option if you do not already have one.
The weekend rule
If your payment deadline falls on a weekend or bank holiday, the money must reach HMRC on the last working day before — unless you are paying by Faster Payments, which clears on the day.
This bites hardest at New Year. A 31 March year end has a corporation tax payment deadline of 1 January, which is itself a bank holiday. Bacs sent on 30 December will not arrive in time.
HMRC’s bank details
| Account | Sort code | Account number |
|---|---|---|
| HMRC Cumbernauld | 08 32 10 | 12001039 |
| HMRC Shipley | 08 32 10 | 12001020 |
Your payslip or HMRC correspondence tells you which one to use. If you are not sure, use Cumbernauld. Payments to the wrong one of the two are generally reconciled, but it adds delay you do not need.
Paying from an overseas account requires HMRC’s IBAN and BIC rather than a UK sort code and account number. These are published on GOV.UK — check them at the time you pay, and expect your bank’s own charges on top.
Two things to do that are not payments
Tell HMRC when no payment is due. If your company owes nothing for an accounting period — a loss, or a dormant period — you can tell HMRC through their online service. Do it. Otherwise HMRC’s system assumes a payment is outstanding and generates reminders and, eventually, chasing correspondence.
Check the payment landed. Your company’s HMRC online account shows payments received and how they have been allocated. Look at it a few days after paying, especially the first time you use a new reference. Catching a misallocation in week one is a phone call. Catching it in month nine is a mess with interest attached.
Groups of companies
If your company is part of a group, HMRC offers a Group Payment Arrangement. One nominated company makes payments on behalf of the group, and those payments are apportioned across group members afterwards.
The benefit is not administrative convenience. It is interest: a group arrangement lets you net off overpayments by one company against underpayments by another, so you avoid paying late payment interest on one company while earning lower repayment interest on another. Given the current spread — 7.75% on late payments against 2.75% on repayments — that gap is worth closing.
You have to apply for the arrangement in advance. It is not something you can invoke retrospectively.
Paying early
HMRC pays credit interest on corporation tax paid early where the liability is not due by instalments, currently 3.50%. Interest runs from the date you pay until the due date, but the earliest date HMRC will pay interest from is six months and 13 days after the start of your accounting period. Pay before that point and the clock simply starts then.
It is not a spectacular return, but it beats leaving the money in a current account and it removes the risk of forgetting.
Frequently asked questions
Why has my corporation tax payment reference changed?
Because it contains a two-digit accounting period number that increments each period. GOV.UK confirms the reference is 17 characters, is specific to an accounting period and changes every period. HMRC’s internal COTAX manual sets out the structure: the first ten digits are your company UTR, A001 identifies corporation tax, and the final character is A. Only the two-digit period number moves — which is exactly why reusing a saved reference sends the money to the wrong period.
What happens if I pay corporation tax with the wrong reference?
GOV.UK warns that your payment may be delayed if you use the wrong reference number. It may be allocated to the wrong accounting period or held in suspense, so the period you meant to pay can show as unpaid, late payment interest accrues at 7.75%, and HMRC may start recovery action. You will need to contact HMRC to have the payment reallocated.
Can I pay corporation tax with a credit card?
Only with a corporate credit card, and a non-refundable fee applies. Personal credit cards are not accepted for corporation tax. A personal debit card is accepted and carries no fee.
Should I pay HMRC Cumbernauld or Shipley?
Your payslip or HMRC correspondence tells you which account to use. If you are not sure, use Cumbernauld — sort code 08 32 10, account number 12001039.
Do I need to tell HMRC if I have no corporation tax to pay?
Yes. If your company owes nothing for an accounting period, tell HMRC using their online service. Otherwise their system treats the payment as outstanding and issues reminders and chasing correspondence for a liability that does not exist.
Get the reference right, then get the return right
Paying corporation tax correctly takes five minutes once you have the right reference in front of you. Working out what to pay is the harder half.
SmartFiling prepares and files CT600 returns on a fixed fee, including the corporation tax computation, capital allowances and HMRC submission, with a three-week turnaround from receiving your records. Every return is reviewed and signed off by an ICAEW Chartered Accountant.
