How to Pay Your Self Assessment Bill: Every Method and Deadline

You can pay your Self Assessment bill by bank transfer, debit card, direct debit, cheque or through your PAYE tax code, and the payment must reach HMRC by 31 January for the tax year that ended the previous 5 April. The fastest routes are online or telephone banking and debit card, which usually arrive the same or next working day; the slowest, such as a posted cheque, need at least three working days. Whichever method you use, quote your 10-digit Unique Taxpayer Reference followed by the letter K, or the payment may not be matched to your record.

• The balancing payment for 2025/26 and your first payment on account for 2026/27 are both due by 31 January 2027.
• Your payment reference is your UTR plus "K" — for example 1234567890K. No spaces.
• Faster Payments, CHAPS and debit card clear same or next working day; Bacs, cheques and paying at a bank take about three working days.
• Personal credit cards are not accepted, and you can no longer pay at the Post Office.
• If you cannot pay in full, a Time to Pay instalment plan can often be set up online, but interest still runs from 1 February.

Every payment method, and how long it takes

HMRC does not care which method you choose, only that cleared funds arrive by the deadline. A payment that leaves your account on 31 January but takes three days to clear is a late payment.

Personal credit cards have not been accepted since 2018, and Post Office payments were withdrawn. If a website or letter tells you otherwise, it is out of date.

Paying by bank transfer

Most people pay Self Assessment by bank transfer from their own online banking. You pay into one of HMRC's two Self Assessment accounts: use HMRC Cumbernauld unless a payslip or statement from HMRC specifically tells you to use HMRC Shipley. The published details are:

• HMRC Cumbernauld — sort code 08 32 10, account number 12001039
• HMRC Shipley — sort code 08 32 10, account number 12001020

If you are paying from an overseas account you need HMRC's IBAN and BIC instead, which are listed on GOV.UK's pay your Self Assessment tax bill page. Payments in a foreign currency are converted at the rate applying when they reach HMRC, so the sterling amount credited can be slightly less than you intended.

Your payment reference: UTR plus K

The single most common reason a Self Assessment payment goes astray is a wrong reference. HMRC needs your Unique Taxpayer Reference — ten digits — with the letter K added on the end. So if your UTR is 1234567890, the payment reference is 1234567890K.

Points that trip people up:

• Do not use your National Insurance number, your PAYE reference, or your VAT number.
• Do not add spaces, hyphens or the word "tax".
• Do not use a reference from a different HMRC bill, such as a Class 2 or PAYE payslip reference.
• Your UTR appears on your Self Assessment statement, on HMRC letters, and in your HMRC online account.

If you pay with the wrong reference the money usually sits unallocated rather than disappearing, but it can take weeks to trace, and penalties and interest keep building in the meantime. Cheques should be made payable to "HM Revenue and Customs only" with your reference written on the back.

Deadlines and cut-offs

There are two payment dates in the Self Assessment year:

• 31 January — the balancing payment for the tax year that ended the previous April, plus the first payment on account for the current year.
• 31 July — the second payment on account.

Interest runs from the day after the due date. HMRC's late payment interest rate is set at the Bank of England base rate plus a fixed margin, so it moves when base rate moves. On top of interest, the classic Self Assessment regime charges a penalty of 5% of the tax still unpaid after 30 days, with further 5% charges at six months and twelve months. If you have been brought into Making Tax Digital for Income Tax — which starts in April 2026 for gross self-employment or property income over £50,000 — different late payment penalty rules apply.

If the deadline falls on a weekend or bank holiday, payment by a method that is not same-day needs to arrive by the last working day before it. Scottish and Welsh taxpayers use exactly the same payment system, references and deadlines; only the rate bands applied to the calculation differ.

Paying in instalments

Time to Pay

If you cannot clear the bill, HMRC's Time to Pay arrangement spreads it over monthly Direct Debits. Many people can set this up themselves online without phoning, provided they have filed the return, owe no more than £30,000, have no other tax debts or payment plans, and arrange it within 60 days of the payment deadline. If you fall outside those limits you can still negotiate a plan by phone using the HMRC difficulties paying service.

Interest continues to accrue on the outstanding balance for the whole life of the plan, so a plan is cheaper than doing nothing but more expensive than paying on time. Keeping to the agreed instalments matters: a missed payment can cancel the arrangement and make the whole balance payable at once.

Budget payment plan

A budget payment plan works the other way round — you pay weekly or monthly by Direct Debit in advance of the bill, building up credit on your record. You can set one up through your HMRC online account if your payments are up to date, and you can pause it for up to six months. It does not reduce the tax due; it just spreads the cash flow.

Through your tax code

HMRC can sometimes collect a Self Assessment balance through PAYE over the following tax year instead. The usual conditions are that you owe less than £3,000, you already have PAYE income, and you filed on time — by 31 October for paper returns or by 30 December for online returns. Miss 30 December and this option closes for that year.

Payments on account: why January is bigger than you expect

Payments on account are advance instalments towards next year's bill. You owe them if your last Self Assessment balance was more than £1,000 and less than 80% of your tax was collected at source. Each instalment is 50% of the previous year's income tax and Class 4 National Insurance. Capital Gains Tax and student loan repayments are excluded from the calculation.

Worked example. A sole trader has taxable profits of £45,000 in 2026/27 and no other income.

1. Income tax: £45,000 − £12,570 personal allowance = £32,430 taxable, all within the £37,700 basic rate band, so £32,430 × 20% = £6,486.
2. Class 4 National Insurance: (£45,000 − £12,570) × 6% = £1,945.80.
3. Total liability: £6,486 + £1,945.80 = £8,431.80.
4. Payments on account for 2027/28: £8,431.80 ÷ 2 = £4,215.90 each.

So if this trader had made payments on account of £3,000 in total during the year, the 31 January 2028 demand would be £8,431.80 − £3,000 = £5,431.80 balancing payment, plus £4,215.90 first payment on account — £9,647.70 in one go, with a further £4,215.90 due on 31 July 2028. That doubling effect is what catches first-time filers.

If you know your income has fallen, you can apply to reduce your payments on account, online or on form SA303. Reduce them too far and HMRC charges interest on the shortfall. The mechanics, including how the instalments interact with your balancing payment, are set out in our guide to payments on account explained.

What to do next

Work out the total figure before you choose a payment method, because the January demand is usually a balancing payment and an instalment combined. Use the Self Assessment tax calculator to check the year's liability, then the payments on account calculator to see what each 31 January and 31 July instalment should be. Once you have the number, pay by a same-day method if the deadline is close, and check your HMRC account a few days later to confirm the payment has been allocated against the right year.