How to Pay Your Self Assessment Tax Bill in 2025/26

If you’re self-employed, a company director, a landlord, or receive untaxed income, you’re probably familiar with HMRC’s Self Assessment system. But while submitting your tax return is a key step, knowing how and when to pay your tax bill is equally important — and failing to do so can result in interest and penalties.

In this guide, we’ll walk you through the process of paying your Self Assessment tax in the 2025/26 tax year, covering:

• Deadlines
• Payment options
• What reference to use
• What to do if you can’t pay on time
• Practical tips to stay on track

Whether it’s your first year under Self Assessment or you simply want to make sure everything’s paid correctly, this blog breaks it down into clear, manageable steps.

When Is Your Self Assessment Tax Due?

In the UK, there are two main tax payment deadlines for individuals in Self Assessment:

✅ 31 January 2026

This is the most important date and covers:

• The balance of your 2024/25 tax liability
• Your first payment on account for 2025/26 (if required)

✅ 31 July 2026

This is the due date for your:

• Second payment on account for 2025/26

Payments on account are advance payments towards your next year’s tax bill and are based on your previous year’s liability. Each payment is typically 50% of the total tax owed (excluding capital gains or student loan repayments).

You can check your payment amounts by logging into your HMRC personal tax account.

How Much Do You Owe?

Before you pay, make sure you:

1. Have filed your tax return

2. Know the total amount due

3. Understand if any payments on account apply

Your tax summary will show:

• Total due by 31 January

• Any advance payments (already made in July)

• What’s left to pay

How to Pay HMRC: Your Options

There are several secure methods for paying your Self Assessment tax bill. Choose the one that suits your situation best, and make sure you allow enough time for the payment to clear.

1. Bank Transfer (Faster Payments, CHAPS, or Bacs)

You can pay directly from your bank account using your online or mobile banking app.

Bank details for HMRC Cumbernauld:

• Sort code: 08-32-10
• Account number: 12001039
• Account name: HMRC Cumbernauld

(If HMRC has told you to pay Shipley, use sort code 08-32-20 and account number 12001020 instead.)

Payment reference: Your 10-digit Unique Taxpayer Reference (UTR) followed by the letter ‘K’.
Example: 1234567890K

This is the most common and reliable method and usually clears on the same day if using Faster Payments.

2. Debit Card or Corporate Credit Card

You can pay online using a debit card or a corporate credit card via HMRC’s card payment page.

Note: HMRC no longer accepts personal credit cards for Self Assessment payments.

3. Direct Debit

You can set up:

• A one-off Direct Debit
• A recurring Direct Debit mandate (ideal for regular payers)

To do this, log into your HMRC online account. The first time you set up a Direct Debit may take up to 5 working days, so allow plenty of time before the payment deadline.

Once set up, future payments are usually quicker — 3 working days or less.

4. HMRC Mobile App

You can use the HMRC app (available on iOS and Android) to pay via:

• Apple Pay
• Google Pay
• Your linked bank account

This method is simple and ideal for individuals managing tax on the go.

5. Cheque by Post

If you prefer traditional methods, you can post a cheque to:

HM Revenue and Customs
Direct
BX5 5BD

Make the cheque payable to:
“HM Revenue and Customs only”
Include your UTR + ‘K’ as the reference on the back of the cheque and enclose a paying-in slip (from HMRC) if you have one.

Allow at least 3 working days for HMRC to receive and process your cheque.

Missed the Deadline? What Happens Next

If you don’t pay your Self Assessment tax on time, HMRC will:

• Charge interest from the day after the deadline
• Add penalties:
  • 5% of unpaid tax after 30 days
  • Additional 5% penalties after 6 months and again at 12 months

Even if you can’t pay in full, don’t ignore the problem.

Can’t Pay Your Tax Bill? Time to Pay May Help

If you’re struggling to pay, HMRC offers a Time to Pay arrangement, which allows you to spread your tax bill over monthly instalments.

You may be eligible to set this up online if:

• You owe less than £30,000
• Your tax return is filed
• You plan to pay it off within 12 months

You can also call the Self Assessment Payment Helpline for help:
 0300 200 3822

Practical Tips for a Smooth Payment Process

Double-check your UTR:
Using the wrong payment reference may delay or misallocate your payment.

Pay early if possible:
Avoid last-minute stress. Faster Payments are usually instant, but Bacs or Direct Debits can take up to 5 working days.

Save proof of payment:
Always screenshot or save payment confirmations in case you need them later.

Keep on top of deadlines:
Set calendar reminders for 31 January and 31 July each year.

Use your online HMRC account:
You can track your payments, view your liabilities, and adjust details easily.

Final Thoughts: Make Paying Tax Less Taxing

Paying your Self Assessment tax doesn’t have to be complicated — but getting it wrong can lead to fines and cash flow issues. With multiple payment options available, it’s simply a matter of choosing the best method for your situation and ensuring you plan ahead.

At Merranti Accounting, we support clients with:

• Tax return submissions
• Calculating what’s due
• Setting up payments correctly
• Managing cash flow ahead of deadlines

Need help making your January or July payments? Let us walk you through it — and make sure you avoid unnecessary penalties.