How to Check and Pay an HMRC Simple Assessment (PA302) (2026/27)

This guide is general information, not advice.

This is for anyone who has opened a letter from HMRC headed Simple Assessment, also known as a PA302. It is a tax bill, not a form to fill in: HMRC has already worked out that you underpaid Income Tax for a past year and could not collect it through your tax code, so it is asking you to pay it directly. A common case, and the one GOV.UK uses as its example, is a pensioner whose State Pension, paid with no tax taken off, pushes their income above their allowances.

By the end you will have checked every figure against your own records, know whether and how to query it, and know the deadline and exactly how to pay with the right reference. If the letter you have is a P800 telling you that you are owed a refund, you want the tax refund guide instead.

Before you start

Gather:

• the Simple Assessment letter itself, by post or in your Personal Tax Account. GOV.UK’s Understand your Simple Assessment tax bill says it shows your taxable income, any Income Tax already paid, the amount you owe and a 14-character payment reference starting with X;
• your P60 (or P45 if you left a job) for the year on the letter;
• pension statements from any private or workplace pension;
• your State Pension or benefit award letter from DWP or Social Security Scotland for that year;
• bank and building society statements showing interest, and any dividend vouchers;
• your National Insurance number, which HMRC’s Income Tax enquiries page asks you to have ready when you phone.

Step-by-step

1. Read why you got it. GOV.UK lists the usual reasons: you “owe Income Tax that cannot be collected through your tax code”, you “owe £3,000 or more in tax”, you “need to pay tax on your State Pension”, or you “have untaxed income (such as savings interest or dividends)”. The £3,000 point ties in with If you owe tax: HMRC usually collects an underpayment through your tax code when you owe less than £3,000.

2. Check each income line against your records. GOV.UK’s check page tells you to match the amounts to your P60 or P45, bank statements, DWP or Social Security Scotland letters, and pension or benefits summaries. For a benefit, take the award letter for the right tax year and annualise it: every 4 weeks, multiply by 13 (not 12); every 2 weeks, multiply by 26; monthly, multiply by 12.

3. Check the State Pension figure the way HMRC works it out. HMRC’s How your State Pension is taxed says that if you started on or after 6 April 2010, a full year is taxed as one week at the old weekly rate plus 51 weeks at the new rate after the April increase, based on what you were entitled to, not what landed in your account. If you started part way through the year, it is the weekly rate times the weeks left in the tax year from your entitlement date.

4. Look for the adjustments section. GOV.UK notes that things such as Marriage Allowance, or tax you owe from a previous year, may not appear as separate lines and are usually folded into the adjustments total. If you want a second view, HMRC’s tax checker can estimate what you should have paid last year.

5. If a figure is wrong, contact HMRC within 60 days. GOV.UK’s If the amounts used in your tax calculation are wrong says to call or write to HMRC within 60 days of the date on your tax bill, telling them which amounts are wrong and what they should be, and explaining which records you used. HMRC may ask to see them. The Income Tax enquiries line is 0300 200 3300, Monday to Friday, 8am to 6pm; the postal address is Pay As You Earn and Self Assessment, HM Revenue and Customs, BX9 1AS.

6. If the figures are right, pay by the deadline. You need the 14-character X reference. GOV.UK’s Pay your Simple Assessment tax bill lists three methods:

   • Pay online: approve a payment through your online bank account, or use a personal debit card or a corporate debit or credit card. You cannot use a personal credit card, and corporate cards carry a non-refundable fee. HMRC accepts the payment on the date you make it, even at weekends and on bank holidays.
   • Bank transfer: sort code 08 32 10, account number 12001020, account name HMRC Shipley. From abroad: IBAN GB03 BARC 2011 4783 9776 92, BIC BARCGB22. Faster Payments usually arrive the same or next day, CHAPS the same working day within your bank’s cut-off, Bacs within 3 working days.
   • Cheque: payable to “HM Revenue and Customs only”, with the X reference on the back, sent to HMRC Direct, BX5 5BD. It must reach HMRC by the deadline.

   You can pay in full or in several smaller payments, provided the whole amount is in by the deadline.

Deadlines and what happens next

The payment deadline. For the 6 April 2025 to 5 April 2026 tax year, GOV.UK says:

• a letter you get before 31 October 2026 must be paid by 31 January 2027;
• a letter you get on or after 31 October 2026, for that year or any earlier one, must be paid within 3 months of the date of the letter.

If you query it. HMRC either agrees and sends a new Simple Assessment, or disagrees and sends a decision letter explaining why, how to pay and how to appeal. You have 30 days from the date of the decision letter to appeal. GOV.UK is clear that you “still need to pay your Simple Assessment tax bill by the deadline unless HMRC tells you they’ll delay your payment date”.

If a second bill arrives. HMRC can send more than one Simple Assessment for a year when new information comes in. The latest one shows the total for the year, including amounts on earlier bills, so you pay only the difference: GOV.UK’s example is a £300 bill paid, then a new one for £450, leaving £150 to pay. If you overpay, you contact HMRC for a refund.

If you cannot pay. Contact HMRC before the deadline. The payment page links to GOV.UK’s If you cannot pay your tax bill on time, and HMRC’s payment problems page has a dedicated Simple Assessment payment line, 0300 322 7835, for anyone who has missed the deadline (Monday to Friday, 8am to 6pm). How a payment plan works, and what HMRC asks about your income and spending, is in how to set up Time to Pay with HMRC.

If you do not pay. HMRC’s Compliance Handbook at CH155200 lists “HMRC making a Simple Assessment” among the Income Tax liabilities that attract a penalty for paying late. HMRC’s What will happen if you do not pay your tax bill says it may keep a repayment you would otherwise receive to clear the debt, adjust your tax code to collect it if you have PAYE income, and use its debt enforcement powers if you do not talk to it about how you will pay.

Common mistakes

• Treating it as a Self Assessment return. GOV.UK says Simple Assessment “is not the same as making a Self Assessment tax return”. There is nothing to file; you check and pay.
• Annualising a 4-weekly benefit by 12. Thirteen 4-weekly payments fall in a year, so multiplying by 12 understates it and makes a correct bill look wrong.
• Comparing the State Pension figure with what you received. HMRC taxes the amount you were entitled to over the tax year, one week at the old rate and 51 at the new one, not the payments that reached your bank.
• Missing the 60 days, or stopping payment while you query. The 60 days runs from the date on the bill, and a query does not move the payment deadline unless HMRC says so.

Worked example

This is GOV.UK’s own example from Understand your Simple Assessment tax bill. It uses the £12,570 Personal Allowance and 20% basic rate that also apply in 2026/27.

• State Pension: £16,000 a year (including Additional State Pension); private pension: £1,500 a year. Total: £17,500.
• Less Personal Allowance £12,570 leaves £4,930 taxable.
• £4,930 × 20% = £986 tax due for the year.
• Through the tax code on the private pension, HMRC collected £750: 50% of the private pension, which GOV.UK says is the maximum that can be collected through the tax code.
• The shortfall of £236 is collected by Simple Assessment after the tax year ends.

To check a bill like this yourself, confirm the State Pension line from your DWP letter using the 1 + 51 week rule, the private pension figure and tax deducted from its P60, and then redo the three lines of arithmetic.

Related reading

• UK tax refund: the complete process - if HMRC owes you money rather than the other way round.
• How to set up a Time to Pay arrangement with HMRC - if you cannot pay the bill by the deadline.
• How to read a PAYE coding notice - to check the tax code that should have collected this tax in the first place.