HMRC Simple Assessment Explained: What It Is and What to Do When You Receive One

Simple Assessment is a system introduced by HMRC in 2017 to allow certain taxpayers to pay tax they owe without needing to complete a full Self Assessment return. Instead of filing a return and calculating your own tax, HMRC does the calculation for you and sends a bill. If you receive a Simple Assessment letter, it means HMRC believes you owe tax that has not been collected through PAYE, and it is asking you to pay.

Who receives a Simple Assessment?

Simple Assessment is used for taxpayers who have relatively straightforward tax affairs but who owe tax that PAYE did not collect. The most common recipients are:

• State Pension recipients: Those whose only income is the State Pension plus a small amount of other income. Because the State Pension is paid gross (without PAYE deduction) and exceeds the Personal Allowance, some tax may be due — but there is no PAYE payroll to collect it from. Simple Assessment is the mechanism HMRC uses.
• People who have underpaid tax through PAYE and whose underpayment is too large to collect via a tax code adjustment (HMRC's threshold for code adjustment is generally underpayments up to £3,000).
• People with savings interest or dividend income above their allowances who are not registered for Self Assessment and are not in PAYE.
• Former Self Assessment filers who no longer need to file a full return but still have a one-off tax debt to settle.

How Simple Assessment works

HMRC uses information it already holds — from employers (via RTI), DWP (for State Pension), banks (interest paid), and other sources — to calculate the tax you owe. It sends you a PA302 letter (the Simple Assessment notice) showing:

• Your income from all sources HMRC is aware of.
• The tax-free amounts and allowances applied.
• The tax owed.
• The payment deadline.

You do not need to fill in any forms. You simply check the calculation, and if it is correct, pay the amount shown. If it is wrong, you can dispute it.

When is payment due?

The payment deadline depends on when HMRC sends the Simple Assessment:

• If sent before 31 October following the end of the tax year, payment is due by 31 January of the following year (the same as Self Assessment).
• If sent after 31 October but before 31 December, payment is due within 60 days of the date on the notice.

Interest accrues on late payments at HMRC's current rate (7.25% in 2025). There are no automatic surcharges for late payment of Simple Assessment (unlike Self Assessment penalties for filing late), but HMRC can enforce collection if you ignore the bill.

What to do when you receive a Simple Assessment

1. Check the figures: Compare the income HMRC has listed against your own records. Common errors include incorrect State Pension amounts, missing savings interest (especially from accounts closed in the year), or income from a previous year incorrectly included.
2. Contact HMRC if anything is wrong: Call HMRC on 0300 200 3300 or write to dispute the assessment. You have 60 days from the date of the notice to challenge it. HMRC will review and issue an amended notice if appropriate.
3. Pay online if correct: You can pay via the HMRC website, bank transfer, or cheque. Reference your Unique Taxpayer Reference (UTR) or National Insurance number as instructed in the letter.

Simple Assessment vs P800

You may also receive a P800 tax calculation, which tells you either that you have overpaid tax (and are due a refund) or underpaid tax. The key difference:

• A P800 showing underpayment typically leads to a tax code adjustment in the following year — not an immediate bill.
• A Simple Assessment (PA302) is an actual demand for payment. You must pay it directly.

HMRC moved away from collecting all underpayments via code adjustments for certain groups (particularly pensioners and those outside PAYE), which is why Simple Assessment exists.

Frequently asked questions

Do I need to register for Self Assessment if I receive a Simple Assessment?

No. Simple Assessment is designed specifically to avoid that requirement. You receive a bill, you check it, and you pay it. You do not gain a UTR or need to file returns. However, if your tax affairs become more complex (rental income, self-employment income, income above £100,000), you may need to register for Self Assessment separately.

What if I genuinely cannot pay?

Contact HMRC as soon as possible to discuss a Time to Pay arrangement. HMRC can allow payment in instalments over a period, typically up to 12 months. Interest continues to accrue on the outstanding balance, but penalties are generally avoided if you proactively engage with HMRC before the deadline.