Simple Assessment: when HMRC works out your bill for you

A Simple Assessment is a tax bill that HMRC works out for you. Officially the letter is known as a PA302, and HMRC sends one when you did not pay enough tax during the year and the shortfall could not be collected through your tax code¹. Around 1.8 million Simple Assessment letters are being issued for the 2025 to 2026 tax year, and HMRC has urged customers not to ignore them².

The letter shows the amount of tax you owe and when that amount is due³. There is no tax return to fill in: HMRC does the calculation itself from information it already holds about your income. Your job is to check the figures against your own records, tell HMRC within 60 days if something looks wrong, and pay what is owed by the deadline, which for the 2025 to 2026 tax year is 31 January 2027 unless the letter shows a different date².

What a Simple Assessment is and why HMRC sends one

Most people pay Income Tax as they go, through PAYE: an employer or pension provider takes tax from each payment before it reaches them, using a tax code that sets how much is taken. At the end of each tax year, which finishes on 5 April, HMRC checks the tax paid against the tax due, using information from employers, pension providers, banks and building societies¹.

When that check shows you paid too little, HMRC first tries to collect the shortfall by adjusting your tax code for a later year, spreading the repayment across your pay or pension. A Simple Assessment is what happens when that is not possible: the amount is too large, or there is no code HMRC can adjust. HMRC then sends you a letter, called a Simple Assessment tax bill or a PA302, setting out the tax due in one calculation¹.

The same check can show you paid too much. In that case HMRC sends a tax calculation letter, known as a P800, instead, and you may be due a refund⁴. So the family of letters after the tax year ends divides in two: a P800 when you overpaid, and a Simple Assessment when you underpaid and the money could not be taken through your code.

HMRC gives a worked example of how this happens. A taxpayer with a £16,000 State Pension and £1,500 of private pension income ended the year with tax still due, and HMRC sent a Simple Assessment after the end of the tax year to collect the remaining £236¹. The amounts vary enormously from person to person; what the example shows is the principle, that the letter is a catch-up bill for tax that slipped through the net during the year.

Who gets a Simple Assessment

You may get a Simple Assessment if you owe Income Tax that cannot be collected through your tax code¹. HMRC's guidance sets out the main situations. You will get one if you owe £3,000 or more in tax, because amounts of that size are generally too large to spread through a code¹. You will also get one if you go over your Personal Allowance and have tax to pay on your State Pension, or if you owe Income Tax that cannot be automatically deducted from your income⁵.

The tax campaign guidance summarises the two headline conditions: you will get a Simple Assessment if you owe more than £3,000, or if your State Pension is your only income and it is more than your Personal Allowance³. That second condition matters because the State Pension is paid without tax taken off at source, so a pensioner whose only income is a State Pension above the allowance has no code through which HMRC can collect the tax during the year.

A Simple Assessment can also arise from savings and investments. If you have tax to pay on interest on savings or dividends, and you do not have a tax code or your code cannot be changed, HMRC may send a Simple Assessment letter⁶. This route has become more common as more people earn enough interest on savings to owe tax on it.

The letter arrives by post or in your Personal Tax Account¹, so it is worth checking your online account as well as your letterbox if you expect one. If you are unsure whether a letter is genuine, see the section on where to get help below, because HMRC letter scams exist.

Where HMRC gets its figures: employers, pensions, banks and building societies

A Simple Assessment is only as good as the information behind it. At the end of each tax year, HMRC checks how much tax you have paid using information from employers, pension providers, banks and building societies¹. Employers and pension providers report pay, pensions and the tax deducted under PAYE; banks and building societies report the interest they paid you, known as Bank and Building Society Interest (BBSI) data².

This reporting is what makes the check possible, and it is also why the timing of letters varies. Pay and pension data arrives with HMRC soon after the tax year ends, which is why the first round of letters can go out in the summer. Bank and building society interest data arrives later, which is why a second tranche of letters follows between October and December².

You are not limited to HMRC's view of your income. You can use the PAYE section of HMRC online services or the HMRC app to check the employers HMRC has recorded for you, your estimated income and your tax codes⁷. Checking these details during the year can reduce the chance of a surprise bill later, because an out-of-date code or a missing employer record is a common cause of underpayment.

The scale of this data is large. HMRC's Survey of Personal Incomes is based on information held by HMRC on individuals who could be liable to UK Income Tax⁸, and HMRC's Income Tax liabilities statistics are built on that survey, a representative sample of individuals in HMRC's PAYE, Self Assessment and repayment claims administrative systems⁹. In other words, the Simple Assessment you receive is drawn from the same records HMRC uses for its national statistics, not from a separate, rougher estimate.

Simple Assessment is not a Self Assessment tax return

The names are confusingly similar, but the two things are quite different. Simple Assessment is not the same as making a Self Assessment tax return¹. A Self Assessment return is something you fill in yourself, declaring your income and working out what you owe; a Simple Assessment is a bill HMRC has already worked out for you, with nothing to fill in.

The two systems are also mutually exclusive for the same person. If you are registered for Self Assessment, you will not receive a Simple Assessment, because your tax is handled through the return instead³. So if you are already filing returns each year, an underpayment is settled through that route, not through a PA302 letter.

Self Assessment exists mainly for people whose tax cannot be handled through PAYE alone: the self-employed, and people who get money from things other than a job, such as investments or renting out a property¹⁰. If your affairs are simple enough that HMRC can see all your income from its own records, a Simple Assessment is the lighter-touch alternative: no registration, no return, no filing deadline, just a bill to check and pay.

If you think you might need to register for Self Assessment, for example because you have become newly self-employed with gross income over £1,000, there is an online registration service available to individual customers with a Personal Tax Account¹¹. First-time filers for the 2025 to 2026 tax year needed to register by 5 October 2026, and the deadline for submitting a return and paying any tax owed for that year is 31 January 2027¹¹.

When the letters arrive: summer and a second round for savings interest

Simple Assessment letters do not all arrive at once. For the 2025 to 2026 tax year, working-age customers began receiving letters from 30 June 2026, and pensioners began receiving them from 12 August 2026². HMRC will issue around 1.8 million Simple Assessment letters in total for the year².

A second tranche of letters will be sent between October and December 2026, relating to Bank and Building Society Interest data². This second round catches people whose underpaid tax comes from savings interest, because the banks' and building societies' reports reach HMRC later than pay and pension data. If you receive a letter in the autumn that mentions interest on savings, it may be your first Simple Assessment for the year, or it may add to one you already had.

Letters for a tax year arrive in waves, with savings interest handled last.

The timing of the underlying check follows a pattern. Tax calculation letters for people who are employed or get a pension are usually sent between June and the following March after the tax year ends⁶. For the current tax year, HMRC adds an estimated amount of savings interest into your tax code, based on the information your bank or building society gave it for the previous year⁶. That estimate is then trued-up against the actual interest paid once the year ends, which is one reason a bill can appear even when your code seemed to cover everything.

Pensioners and the State Pension

Pensioners are the group most likely to receive a Simple Assessment, and the reason lies in how the State Pension is paid. The State Pension is taxable income, but tax is not taken off it before it is paid. Instead, HMRC normally collects the tax by adjusting the tax code on any other pension or earnings you have, so that the extra tax covers the State Pension too¹².

When that is not possible, because there is no other income large enough to carry the adjustment, or the code cannot be changed, HMRC may send a Simple Assessment tax calculation after the end of the tax year¹². This is the situation described in the eligibility rules: if your State Pension is your only income and it is more than your Personal Allowance, you will get a Simple Assessment³.

The numbers involved are substantial. Official statistics show 8,576 thousand people, 69% of State Pension Age claimants in England and Wales, were in the "State Pension only" benefit combination as of March 2026¹³. Not all of them owe tax, but anyone whose State Pension alone exceeds the Personal Allowance is in the frame for a letter, because there is no other income through which the tax can be collected.

The State Pension is not the only pension income that can trigger a bill. HMRC's pension guidance notes that a Simple Assessment may be sent if you go over your Personal Allowance and have tax to pay on your State Pension, if you owe Income Tax that cannot be automatically deducted, or if you owe £3,000 or more⁵. Private and workplace pensions are taxed through PAYE, so they usually feed into the same year-end check rather than causing a separate bill.

How to pay your Simple Assessment bill

Paying a Simple Assessment is deliberately straightforward. Customers can pay using the free and secure HMRC app, online via GOV.UK, by bank transfer or by cheque². Payments can be made in full or in instalments before the deadline, and no tax return is required². That last point is worth repeating to yourself if you are used to Self Assessment: there is nothing to file, only a bill to settle.

The deadline for the 2025 to 2026 tax year is 31 January 2027, unless a different date is shown on the letter². Always check the letter itself rather than assuming, because HMRC states the date may differ. This is the same deadline that applies to Self Assessment bills for the same tax year, where payment is due by midnight on 31 January following the tax year you are paying for¹⁴.

If a payment deadline falls on a weekend or bank holiday, make sure your payment reaches HMRC by the last working day before, unless you are paying by Faster Payments¹⁵. Cheque and bank transfer payments take time to clear, so leaving payment to the final day can mean an accidental miss.

A note on instalments: HMRC says payments can be made in instalments before the deadline², but the instalments are yours to arrange and complete within the overall deadline. Unlike some tax debts, there is no separate instalment plan deadline stated in the guidance, so the safe approach is to start early enough that the final instalment lands before the due date.

Disagreeing with the figures: 60 days to challenge

The figures in a Simple Assessment come from HMRC's records, and records can be wrong or incomplete. You have 60 days from the date of the letter to let HMRC know if anything does not look right³. That is a firm window, so it is worth checking the letter against your own records as soon as it arrives rather than putting it aside.

What to check: the income listed (pay, pensions, savings interest), the amounts of tax already paid, and the calculation itself. Your P60, pension statements and bank interest statements are the natural documents to compare against. If you have several sources of income, check each one, because a single missing or duplicated figure changes the whole bill.

What to do when the letter arrives, from checking to paying or challenging.

If you miss the 60-day window, the assessment stands as issued, and your route to challenge it becomes narrower and more formal. If you disagree with HMRC's response to a query, or with a decision after the window has passed, the options include asking for an HMRC internal review or appealing to a tax tribunal, which are covered in detail elsewhere on this site.

One point on Scotland: being a Scottish taxpayer changes the rates and bands applied to your income, but not the process. Scottish taxpayer status is based on where an individual resides in the course of a tax year and applies for a whole tax year at a time; the location of a person's employer is not relevant, so someone who works in Scotland but lives elsewhere is not a Scottish taxpayer on that basis alone¹⁶. The checking and paying steps are the same wherever in the UK you live.

Paid too much or received a letter in error

Not every Simple Assessment letter is right, and some should not have been sent at all. If you pay too much, you will need to contact HMRC for a refund¹. This can happen if the figures in the assessment were too high, for example because income was double-counted or a figure was out of date, and you paid the bill as issued.

Revised letters are a recognised part of the process. HMRC's own guidance includes an example in which a taxpayer received a revised Simple Assessment: the original bill was changed, and because the taxpayer had already paid £300, only the remaining £150 needed to be paid¹. The lesson from that example is to read any second letter carefully before paying anything, because it may replace the first bill rather than add to it.

If the letter appears to have been issued in error, for example because there was no liability for the tax at all, or because income was recorded wrongly, the route is the same 60-day query process: HMRC is told within 60 days of the letter date what looks wrong³. Someone registered for Self Assessment does not fall within Simple Assessment³, so a letter arriving despite registration is itself something to raise with HMRC.

If you have overpaid tax more broadly, whether through PAYE or through a Simple Assessment, HMRC's overpayments and underpayments guidance covers how refunds are handled⁴, and our page on claiming a refund when you have overpaid income tax explains the process in full.

Where to get help

Several free sources of help exist for Simple Assessment problems. HMRC itself is the first stop for queries about a bill: the contact details are on the letter, and the query process is the 60-day route described above. For general checking of your tax position, the HMRC app and online account let you see your income records and tax codes as HMRC holds them⁷.

For independent help, TaxConfident, HMRC's own campaign guidance, explains common letters including the PA302 and what to do about them³. If your difficulty is affording the bill rather than understanding it, telling HMRC early matters, because payments can be made in instalments before the deadline².

Be alert to scams around tax letters. HMRC publishes tips on avoiding Self Assessment tax scams, and the same caution applies to Simple Assessment: a genuine HMRC letter will not demand immediate payment to a private bank account or threaten arrest over the phone¹⁷. Our page on fake HMRC calls, texts and emails covers the warning signs. If you want to complain about how HMRC has handled your case, rather than about the bill itself, how to complain about HMRC and escalate to the Adjudicator sets out the route.