Self Assessment Payment Methods and Deadlines Explained

Filing your Self Assessment return is only half the job. You also need to pay what you owe, on time, to the right account and with the right reference. Missing a payment deadline can lead to interest and penalties even if your return was filed perfectly. This guide covers the main deadlines, the payment methods, and the habits that avoid last-minute problems.

Key takeaways

• The main payment date for most taxpayers is 31 January after the tax year ends.
• If you make payments on account, a second payment falls on 31 July.
• Use the correct payment reference and make sure the money arrives by the deadline, not just leaves your account.
• Pay early. Weekends and bank holidays can delay transfers.
• If you cannot pay, contact HMRC before the deadline.

What is due and when?

A tax year runs from 6 April to 5 April. For example, the 2025/26 tax year ends on 5 April 2026. The online return for that year and the main payment are both normally due by 31 January 2027. Confirm your own dates in your HMRC online account or on GOV.UK's Self Assessment deadlines page.

Payments on account in brief

If your bill is above a certain level, HMRC usually asks for two advance payments towards the next year's tax. Many first-time filers are surprised because the 31 January payment can include the previous year's balance plus the first advance payment. We explain this in our guide to payments on account.

Ways to pay

HMRC accepts several methods, and the available options and bank details can change, so always check the current list on GOV.UK's pay your Self Assessment bill page. Typical options include:

• Online or telephone banking. A Faster Payment using the HMRC account details shown on GOV.UK.
• Debit card online. Convenient, but check whether any fee applies to your card type.
• Your online bank account. Some banks let you pay straight from the HMRC payment service.
• Time to Pay arrangement. If you cannot pay in full, ask about spreading the cost. Interest may still apply.

Be careful with scam messages. HMRC does not ask for payment details by random text or email. Always start from GOV.UK.

Getting the reference right

Your payment reference is usually your 10-digit Unique Taxpayer Reference followed by the letter K, but check the exact format for your payment method on GOV.UK. A payment with the wrong reference can sit unallocated, which risks late-payment interest and penalties. If you registered recently, remember it can take time for your UTR to arrive. Our registration guide explains the timing.

Worked example (illustrative)

"Nadia", an illustrative example, files her return in mid-January and sees her bill in her online account. She does not wait until the last day. A week before the deadline she pays by bank transfer, using the details from GOV.UK and her reference. She checks her HMRC account a few days later and sees the payment recorded. In contrast, "Sam", another illustrative example, transfers money on the evening of 31 January using a method that takes days to clear. His payment arrives late, and he may face interest. Both owe the same tax, but only one planned for timing.

Building a payment habit

1. Open a separate savings pot for tax and add to it every month.
2. Check your HMRC online account after filing to confirm the amount due.
3. Pay at least a few working days before the deadline.
4. Keep proof of payment with your tax records.
5. Diarise 31 July if you have payments on account.

Common mistakes

• Paying on the deadline day. A delay in clearing can make the payment late.
• Using an old or wrong reference. Check it each time.
• Forgetting the second payment on account. The 31 July payment catches many people out.
• Not saving as you earn. A large bill can be hard to meet at once.
• Ignoring the problem. If you cannot pay, contact HMRC early to discuss options.

We can prepare your return, tell you what to put aside, and remind you of each deadline. See our Personal Tax service or contact us.