Getting the money to HMRC is the easy part. Getting it to land against the right account, on the right date, is where people come unstuck — usually because of an eleven-character reference number.
Here is every route, what each one costs, how long it takes, and what happens if you miss the date.
Start with the reference number
Your Self Assessment payment reference is your 10-digit Unique Taxpayer Reference followed by the letter ‘K’. Eleven characters, no spaces. A UTR of 1234567890 gives a payment reference of 1234567890K.
You will find it in your HMRC online account, or on your paying-in slip if you still get paper statements. HMRC is explicit that using the wrong reference may delay your payment — and a delayed payment is treated as a late payment, with interest running from the original due date.
This is different from the Corporation Tax reference, which is seventeen characters and changes every accounting period. The Self Assessment reference stays the same for you, permanently. That makes it safe to save as a payee in your banking app — one of the few HMRC references where reusing a saved payee is not a trap.
Every payment method and how long it takes
| How long it takes | Method |
|---|---|
| Same or next day | Approving a payment through your online bank account · Faster Payments (online or telephone banking) · CHAPS · debit or corporate credit card online · at your bank or building society |
| 3 working days | Bacs · Direct Debit if you have set one up with HMRC before |
| 5 working days | Direct Debit if you have not set one up with HMRC before |
You can no longer pay at the Post Office.
If a deadline falls on a weekend or bank holiday, your payment must reach HMRC on the last working day before — unless you pay by Faster Payments or by card, both of which are credited on the day you make them.
To pay at a bank or building society you need a paying-in slip from HMRC. If you do not have one, that route is closed to you.
HMRC bank details
For Faster Payments, CHAPS or Bacs, pay into one of these accounts. Your bill tells you which. If you do not have a bill or you are unsure, either account is fine.
| Account | Sort code | Account number |
|---|---|---|
| HMRC Cumbernauld | 08 32 10 | 12001039 |
| HMRC Shipley | 08 32 10 | 12001020 |
Paying from an overseas account, use the BIC BARCGB22 with IBAN GB62 BARC 2011 4770 2976 90 (Cumbernauld) or GB03 BARC 2011 4783 9776 92 (Shipley). HMRC’s banking address is Barclays Bank PLC, 1 Churchill Place, London E14 5HP. Some banks charge if you do not pay in pounds sterling, and overseas payments can take longer.
Paying by card
You cannot pay by personal credit card. That route closed years ago and is not coming back.
A personal debit card is free. A corporate credit card or corporate debit card carries a fee, and the fee is not refundable. Use the same eleven-character reference.
The useful feature of card payments is timing: HMRC accepts your payment on the date you make it, not the date it reaches their account — including weekends and bank holidays. If you are paying at 11pm on 31 January, a debit card is the safest option available.
Paying by cheque
Cheques are still accepted for Self Assessment, which is worth noting because Corporation Tax cannot be paid by post at all.
Make the cheque payable to ‘HM Revenue and Customs only’ and write your eleven-character reference on the back. Send it to:
HMRC
Direct
BX5 5BD
No street name, city or PO box is needed. Include your payslip if you get paper statements, and do not fold or fasten the cheque and payslip together. The cheque must reach HMRC by the deadline, so allow real posting time — this is the slowest route by a distance.
Paying through your tax code
If you owe less than £3,000, already pay tax through PAYE, and file online by 30 December (or on paper by 31 October), HMRC can collect the bill through next year’s tax code in twelve equal instalments alongside your normal deductions.
HMRC does this automatically if you meet all three conditions, unless you tell them not to on your return. You cannot make a part payment to bring yourself under £3,000 — the test is what you owe in full. It also will not work if you do not have enough PAYE income, if it would take more than 50% of your PAYE income in tax, or if it would more than double your usual tax. Class 2 National Insurance cannot be collected this way.
Paying in instalments before the deadline
A Budget Payment Plan lets you make weekly or monthly Direct Debit payments towards your next bill. You must be up to date with your last Self Assessment payments to set one up, and you can pause payments for up to six months. Anything you have paid in reduces what is due on 31 January; if you have overpaid, you can ask for a refund.
This is for bills that are not yet due. If a bill is already overdue, you need Time to Pay instead.
What happens if you pay late
Interest runs from the day after the due date. The late payment rate is 7.75% — the Bank of England base rate plus 4%.
On top of interest, most taxpayers face a late payment penalty of 5% of the unpaid tax at 30 days, again at 6 months, and again at 12 months.
A different regime now exists for taxpayers mandated into Making Tax Digital for Income Tax and for MTD volunteers, and it extends to everyone from April 2027. Under it, nothing is charged for the first 15 days; 3% of the tax owed is charged at day 15 where the debt is still outstanding between days 16 and 30; and a further 3% is charged at day 30. On top of those, an annual rate of 10% on the outstanding amount is charged daily from day 31 until the tax is paid, or for up to 2 years. For 2027/28 the 3% figures become 4%. A first-year concession gives 30 days to pay or agree a plan before penalties start, reducing to 15 days thereafter.
One important detail: late payment penalties do not apply to payments on account. Interest still does.
If you cannot pay: Time to Pay
HMRC’s payment plan service lets you spread an overdue Self Assessment bill by Direct Debit. To set one up online you must:
- be up to date with your tax returns
- owe £30,000 or less
- have no other tax debts
- have no other HMRC payment plans in place
Interest is charged at the Bank of England base rate plus 4% for the life of the plan. If you owe more than £30,000 or cannot use the online service, HMRC’s payment support line can consider a plan over the phone — you will be asked about your income, spending, savings and assets.
Contact HMRC before the deadline rather than after it. Setting up an arrangement does not remove interest, but it demonstrably changes how the debt is handled.
Frequently asked questions
What is my Self Assessment payment reference?
Your 10-digit Unique Taxpayer Reference followed by the letter ‘K’ — eleven characters in total. You will find it in your HMRC online account or on your paying-in slip. Using the wrong reference may delay your payment.
Which HMRC bank account should I pay into?
Sort code 08 32 10, then account 12001039 for HMRC Cumbernauld or 12001020 for HMRC Shipley. Your bill tells you which. If you do not have a bill or are unsure, either account is accepted.
Can I pay my Self Assessment bill with a credit card?
Not a personal credit card. A corporate credit card is accepted but carries a non-refundable fee. A personal debit card is free.
How long does a Self Assessment payment take to reach HMRC?
Faster Payments, CHAPS, online bank approval and card payments arrive the same or next day. Bacs and an existing Direct Debit take three working days. A first-time Direct Debit takes five.
What interest does HMRC charge on late Self Assessment tax?
7.75%, which is the Bank of England base rate plus 4%. It runs from the day after the due date until the tax is paid, on top of any late payment penalties.
Getting the bill right in the first place
Most payment problems start upstream — a return filed late, a payment on account nobody expected, or a figure that turns out to be wrong. Knowing the number early gives you months to plan the payment rather than days.
SmartFiling files Self Assessment returns for a fixed fee with a three-week turnaround from receiving your records, so you know what you owe well before 31 January. Every return is reviewed and signed off by an ICAEW Chartered Accountant.
