Written by Hammad Rasool MAAT·AAT licensed accountant·Updated November 2026
Budget 2026 update: From April 2029 people who make payments on account will have to make more regular payments during the year. The detail has not been published yet. See everything that changed.

What the statement is

HMRC sends a Self Assessment statement, usually marked SA300, when there is tax to pay or a change on your account. GOV.UK simply calls it your bill. You can see the same information at any time in your HMRC online account.

The lines that matter

  • Balancing payment: the tax still due for the year just ended, after taking off anything you have already paid towards it.
  • First payment on account: an advance payment towards the next tax year. Due by midnight on 31 January.
  • Second payment on account: the other half of the advance payment. Due by midnight on 31 July.
  • Interest and penalties: added if earlier payments or returns were late.
  • Payments received: what HMRC has had from you. Check every payment you made is listed.

How payments on account work

Each payment on account is half of your previous year's tax bill, including Class 4 National Insurance if you are self employed. You do not have to make them if your last bill was less than £1,000, or if more than 80% of the tax you owed was already collected at source, for example through your tax code.

Example

Your tax bill for 2025/26 is £3,000 and it is your first year. On 31 January 2027 you pay the £3,000 plus a first payment on account of £1,500 towards 2026/27, so £4,500 in total. Another £1,500 is due on 31 July 2027. If your 2026/27 bill then turns out to be £3,400, you pay the £400 difference by 31 January 2028.

Key point: the first January under Self Assessment is the expensive one, because you pay a full year plus half of the next. Putting money aside each month from the start avoids the shock.

If your income has dropped

If you expect a lower bill next year, you can ask HMRC to reduce your payments on account, either in your online account or with form SA303. Be careful with the estimate. If you reduce them too far and the final bill is higher, HMRC charges interest on the difference.

If the statement looks wrong

  1. Check payments: a payment made with the wrong reference may be sitting unallocated. Your reference is your 10 digit UTR followed by the letter K.
  2. Check the return: compare the statement with your SA302 tax calculation for the same year.
  3. Check for old years: a balance brought forward from an earlier year is a common surprise.

If you cannot pay

Contact HMRC before the due date. You may be able to set up a payment plan and pay in instalments. Interest still runs, but agreeing a plan in time can prevent late payment penalties.

Common questions

When is my Self Assessment bill due?
The bill for a tax year is due by midnight on 31 January following the end of that year. If you make payments on account, the second instalment is due by 31 July.
Why is my bill higher than my tax calculation?
Usually because the statement includes a payment on account towards next year on top of the tax for the year just ended.
Do I have to make payments on account?
Not if your last Self Assessment bill was less than £1,000, or if more than 80% of your tax was collected at source.
Can I reduce my payments on account?
Yes, online or using form SA303, if you expect your next bill to be lower. If you reduce them too much, HMRC charges interest on the shortfall.

Checked against GOV.UK on 10 November 2026: Understand your Self Assessment tax bill, Payments on account.

About the author

Hammad Rasool MAAT is an AAT licensed accountant based in Bolton. TaxTune Accountants looks after sole traders, landlords, contractors and limited companies in Bolton, Wigan, Bury, Salford, Oldham, Stockport and Manchester, and online across the UK.