HMRC Simple Assessment 2025: What It Is and How to Pay
If you receive a letter from HMRC saying you owe tax but have never filed a Self Assessment return, you may have received a Simple Assessment. Introduced in 2017, Simple Assessment allows HMRC to calculate your tax liability and send you a bill — without requiring you to complete a full Self Assessment return.
What is Simple Assessment?
Simple Assessment (SA302-style calculation sent directly by HMRC) is used for individuals with straightforward tax affairs who are not already in the Self Assessment system. HMRC uses information it already holds — from employers, pension providers, banks, and the Department for Work and Pensions — to calculate what you owe.
You will receive Simple Assessment if HMRC determines that:
- You have underpaid tax through PAYE that cannot be collected via a tax code adjustment
- You receive the State Pension in excess of your Personal Allowance
- You have income from other sources not captured through PAYE
Simple Assessment vs P800
| Document | What it means | Action required |
|---|---|---|
| P800 (tax calculation) | HMRC thinks you have overpaid — a refund is due | Claim online or wait for cheque |
| Simple Assessment letter | HMRC thinks you owe tax | Pay within 60 days or dispute |
How to pay a Simple Assessment bill
HMRC will give you a 60-day window from the date of the letter to pay. Payment options include:
- Online via your HMRC personal tax account (www.gov.uk/pay-self-assessment-tax-bill)
- Bank transfer (BACS/CHAPS) using the reference on the letter
- Debit card online
- Cheque payable to "HM Revenue and Customs"
How to dispute a Simple Assessment
If you think the calculation is wrong, you can challenge it within 60 days of the date on the letter. Common reasons to dispute:
- HMRC has incorrect income figures (e.g., used gross rather than net pension income)
- You have allowances or reliefs that HMRC was not aware of
- The State Pension figure used is incorrect
Contact HMRC by phone (0300 200 3300) or in writing. Keep a copy of all correspondence.
Does Simple Assessment replace Self Assessment?
No. If your tax affairs are complex — for example, you have rental income, are self-employed, or have capital gains — you still need to register for and complete a Self Assessment tax return. Simple Assessment is only suitable for individuals with straightforward, PAYE-based income.
Frequently asked questions
Can I ignore a Simple Assessment letter?
No. If you do not pay within 60 days, HMRC will charge interest and may issue penalties. If you disagree with the amount, dispute it — but do not simply ignore the letter.
What if I cannot afford to pay the Simple Assessment amount?
Contact HMRC before the 60-day deadline to discuss a Time to Pay arrangement. HMRC can spread the payment over several months, though interest will accrue on the outstanding balance.
Will I get Simple Assessment every year?
Not necessarily. If HMRC can correct an underpayment through your PAYE tax code in the following year, it will usually do so rather than send a Simple Assessment. You are more likely to receive Simple Assessment if the underpayment is too large to collect through a code adjustment within a single year.