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Statement · SA300

Self Assessment statement (SA300)

For HMRC's Self Assessment statement, the summary of what you owe and what you have paid. This page sets out what each part means, how to pay and what GOV.UK says if you cannot pay all at once, with each source and the date it was checked.

Last reviewed 8 October 2026 · How Tax Letters checks its facts

The short answer

What this letter is
A Self Assessment statement is a summary of what you owe and the payments you have made. It shows any payments on account due, payments made (marked CR), any amounts outstanding and the balancing payment. [1]
When to pay
GOV.UK says you need to pay your Self Assessment tax bill by midnight on 31 January following the tax year you are paying for, to avoid a penalty. [2]
Payments on account
Payments on account are payments towards your next tax bill, each half of the tax you owed last year, due by midnight on 31 January and 31 July. [3]
Your options at a glance

Every fact on this page comes from a source listed at the foot of the page, with the date it was last checked. All sources and dates

The date on your statement

Due byas printed on your statementGOV.UK says you need to pay your Self Assessment tax bill by midnight on 31 January following the tax year you are paying for, to avoid a penalty.
[2]

If your statement shows payments on account

Due byas printed on your statementPayments on account are payments towards your next tax bill, each half of the tax you owed last year, due by midnight on 31 January and 31 July.
[3]

What the statement shows

A Self Assessment statement is a summary of what you owe and the payments you have made. It shows any payments on account due, payments made (marked CR), any amounts outstanding and the balancing payment. [1]

GOV.UK says that if you pay Self Assessment tax late you get penalties of 5% of the tax unpaid at 30 days, 6 months and 12 months, and you are also charged interest on the amount owed. [4]

If your statement shows payments on account

Payments on account are payments towards your next tax bill, each half of the tax you owed last year, due by midnight on 31 January and 31 July. You do not have to make payments on account if the tax you owed last year was less than £1,000, or if you paid more than 80% of the tax you owed outside Self Assessment, for example through your tax code. [3]

Paying it

Pay

Use the 11-character payment reference printed on your statement, which is a 10-digit number followed by the letter K. GOV.UK says that with the wrong reference “your payment may be delayed or used to pay a different tax bill that you owe”. You can make more than one payment towards a Self Assessment bill before the deadline, as long as it reaches HMRC by the 31 January or 31 July deadline. If a payment has paid the wrong tax bill, GOV.UK says you can contact Self Assessment general enquiries to ask for it to be moved. GOV.UK says you will be charged interest and may be charged a penalty if your payment is late, and that the time to allow depends on how you pay. Paying through your online bank account, by Faster Payments, CHAPS, debit or corporate credit card online, or at your bank or building society takes the same or next day. Bacs, and a Direct Debit you have set up before, take 3 working days. A new Direct Debit takes 5 working days. If the deadline falls on a weekend or bank holiday, GOV.UK says to make sure the payment reaches HMRC on the last working day before, unless you pay by Faster Payments or by debit or credit card. [5] [6]

Ask about a figure

HMRC's Self Assessment general enquiries line is 0300 200 3310, open Monday to Friday, 8am to 6pm, and closed on bank holidays. [7]

Cannot pay it all at once

If you cannot pay your tax bill in full, you may be able to set up a payment plan to pay it in instalments. HMRC will check if a payment plan is affordable for you. If your bill is not overdue, you may be able to set up a Budget Payment Plan to make weekly or monthly payments towards your next Self Assessment bill. GOV.UK: if you cannot pay your tax bill on time [8] [9]

Vision Consulting, Tax Letters' founding partner, also helps with payment plans: visionconsulting.co.uk/hmrc-time-to-pay

If one of these is you

Your bill is not overdue and you would rather pay as you go

If your bill is not overdue, you may be able to set up a Budget Payment Plan to make weekly or monthly payments towards your next Self Assessment bill. [9]

Someone helps you with your tax

You can authorise a friend, relative or voluntary organisation to talk to HMRC for you and help you fill in forms. You can also authorise an agent, such as an accountant or tax adviser, to deal with HMRC for you. [10]

Your health or circumstances make this hard

HMRC offers extra support if your health condition or personal circumstances make it difficult to contact HMRC, for example a mental health condition, financial hardship or being treated in hospital. You can ask for an appointment with HMRC's extra support team when you call a helpline, through its webchat, or in British Sign Language, and home visits can be asked for with an online form. [11]

If your statement shows payments on account

You expect your tax to be lower than last year

If you know the tax you owe is going to be lower than last year, GOV.UK says you can ask HMRC to reduce your payments on account, online or by post on form SA303, giving the amount you expect to make. GOV.UK says that if you reduce your payments on account and your tax bill is higher than expected, you will be charged interest on the difference. [3]

Is it real

This page cannot prove a statement is genuine. One check that does not rely on the statement: sign in to your HMRC account yourself, from GOV.UK. Another is HMRC's own list of genuine contacts. HMRC's lists describe emails, phone calls, letters and text messages it has recently issued. Not every HMRC communication is included. [12]

Keep it and get help

Keep this with the statement. Mark what you did:

Paid on ____________Called about it on ____________Set up a payment plan on ____________

You can always deal with HMRC directly, free, without any service or adviser. Free help: TaxAid, which says it helps “people who can’t afford to pay for help”, and Citizens Advice. [13] [14]

Sources

Each source is linked, with the date Tax Letters last checked it.

  1. GOV.UK: Understand your Self Assessment tax bill, the statement (checked 7 Oct 2026)
  2. GOV.UK: Understand your Self Assessment tax bill (checked 7 Oct 2026)
  3. GOV.UK: Understand your Self Assessment tax bill, payments on account (checked 7 Oct 2026)
  4. GOV.UK: Self Assessment tax returns, penalties (checked 7 Oct 2026)
  5. GOV.UK: Pay your Self Assessment tax bill (checked 7 Oct 2026)
  6. GOV.UK: Pay your Self Assessment tax bill (checked 8 Oct 2026)
  7. GOV.UK: Self Assessment: general enquiries (checked 7 Oct 2026)
  8. GOV.UK: If you cannot pay your tax bill on time (checked 7 Oct 2026)
  9. GOV.UK: If you cannot pay your tax bill on time, setting up a payment plan (checked 7 Oct 2026)
  10. GOV.UK: Appoint someone to deal with HMRC on your behalf (checked 7 Oct 2026)
  11. GOV.UK: Get help from HMRC if you need extra support (checked 7 Oct 2026)
  12. GOV.UK: Check a list of genuine HMRC contacts (checked 7 Oct 2026)
  13. TaxAid: About us (checked 8 Oct 2026)
  14. Citizens Advice: About us (checked 7 Oct 2026)