Why You Might Be Getting a Surprise Simple Assessment Letter From the Taxman, and What It Might Cost You

HMRC is sending out around 1.8 million Simple Assessment letters this summer, and if one lands on your doormat, it's worth reading properly rather than putting it in the pile of post you'll get to later!

These letters tell you if you owe tax that couldn't be collected automatically, and with savings rates having climbed this year, more people than ever may be getting one for the first time simply because their savings interest finally tipped them over into taxable territory.

What is a Simple Assessment letter and why might you get one?

A Simple Assessment letter, officially known as a PA302, is HMRC's way of telling you that you owe tax it couldn't collect through your tax code or a Self Assessment return. It sets out exactly how much you owe and explains why, so you don't need to work anything out yourself.

You might receive one for several reasons. You could have tax to pay on interest from savings or dividends, a second income that hasn't been taxed, tax due on pension income, or you may simply have received more tax-free allowance than you were entitled to. HMRC also sends one when the amount owed is too large to collect through an adjustment to your tax code, which typically means £3,000 or more.

These letters are generated automatically once HMRC receives data from employers, the Department for Work and Pensions, and financial institutions confirming that tax is due. It's a routine annual process rather than a sign that anything unusual has happened, so there's no need to panic if one arrives; just check it against your own records and act on it.

When will you receive your letter?

Timing depends on your circumstances. Working-age customers began receiving letters from the 30th of June, so if you're going to get one for this reason, it may already have arrived.

Pensioners will start receiving theirs from the 12th of August, and a second batch of letters goes out between October and December specifically covering Bank and Building Society Interest, which is the one most likely to catch savers by surprise given how much interest rates have moved this year.

If you've never had taxable savings interest before, that October to December batch is the one worth watching for. Rates on fixed savings accounts have risen enough over the past year that many people are now earning more interest than their Personal Savings Allowance covers, without changing how they save.

How much could you owe, and when do you need to pay?

The amount on your letter depends entirely on your own income and circumstances, so there's no single figure to expect. What matters is checking it against your own records, since HMRC builds the calculation from data submitted by employers and financial institutions, and mistakes on that underlying data do happen occasionally.

Payment is due by the 31st of January 2027 for letters covering the 2025 to 2026 tax year, unless your specific letter shows a different date. You can pay the full amount at once or spread it across instalments before the deadline, and you won't need to complete a tax return for the income covered by the letter.

Payment can be made through the HMRC app, online via GOV.UK, by bank transfer, or by cheque.

HMRC's Chief Customer Officer, Myrtle Lloyd, has urged anyone who receives a letter and has tax to pay not to ignore it, pointing out that paying through the HMRC app is quick, and that anyone needing extra support can search "Simple Assessment" on GOV.UK for further guidance.

How to check a Simple Assessment letter is genuine

Given how common fake tax letters, texts and calls have become, it's a fair question to ask. Genuine Simple Assessment letters arrive by post or appear in your Personal Tax Account online, and GOV.UK provides a way to check if a letter from HMRC is genuine if anything about yours feels off. HMRC will never ask you to pay by transferring money to a personal bank account or by buying vouchers, so treat any letter, text or call demanding payment that way as an immediate red flag.

If you're at all unsure, don't use any link, number or QR code printed on the letter itself. Go directly to GOV.UK and search for Simple Assessment, or check your Personal Tax Account by logging in through the official GOV.UK route rather than any link you've been sent.

The one thing worth taking from all of this is that a Simple Assessment letter isn't something to dread, it's HMRC doing the sum for you rather than leaving you to work it out. Check it against what you know about your own income, pay by the deadline through whichever method suits you, and if anything about the letter itself looks unfamiliar, verify it on GOV.UK before you do anything else.

FAQ

What is a Simple Assessment letter? A Simple Assessment letter, officially called a PA302, is sent by HMRC when you owe tax that couldn't be collected automatically through PAYE or Self Assessment. It sets out exactly how much you owe and why.

Is a Simple Assessment letter from HMRC genuine? It can be, since HMRC sends these letters by post or through your Personal Tax Account every year as part of routine processes

. If you're unsure, check it directly on GOV.UK rather than clicking any links in a text or email claiming to be HMRC.

What is a PA302 letter? PA302 is the official name for a Simple Assessment tax calculation letter. It's the same thing as a Simple Assessment letter, just referred to by its form number.

When do I have to pay my Simple Assessment tax bill? Payment is due by the 31st of January 2027 for letters covering the 2025 to 2026 tax year, unless a different date is shown on your specific letter. You can pay in full or set up instalments before that date.

Do I need to file a tax return if I get a Simple Assessment letter? No, that's the entire point of Simple Assessment. HMRC calculates what you owe and tells you directly, so no tax return is needed for the income covered by the letter.