If you’ve recently received a letter from HMRC headed “Simple Assessment”, you’re not alone. More taxpayers are receiving these letters as HMRC expands its use of digital records and automated tax calculations.
A Simple Assessment doesn’t necessarily mean you’ve made a mistake. It simply means HMRC believes it has enough information to calculate your tax liability without asking you to complete a Self Assessment tax return.
Here’s what you need to know.
What Is a Simple Assessment?
A Simple Assessment is a tax calculation issued by HMRC when it already holds sufficient information to work out the tax you owe but cannot collect it automatically through the Pay As You Earn (PAYE) system.
Instead of requiring you to submit a Self Assessment tax return, HMRC calculates your tax liability and sends you a Simple Assessment showing:
- The amount of tax due
- How the calculation has been made
- Your payment deadline
- How to query or appeal the assessment if you believe it is incorrect
Who Receives a Simple Assessment?
HMRC may issue a Simple Assessment where it believes additional tax is due and it cannot be collected automatically through PAYE.
This commonly applies to people who have:
- Underpaid tax on employment income.
- Underpaid tax on pension income.
- State Pension income that has not been fully taxed.
- Multiple sources of income where PAYE deductions were insufficient.
- A tax liability of £3,000 or more that cannot be collected through adjustments to their tax code.
- Tax to pay after their employment or PAYE income has ended.
HMRC uses information provided by employers, pension providers, the Department for Work and Pensions (DWP), banks, building societies and other financial institutions to calculate the tax due.
Simple Assessment vs Self Assessment
Although both systems are used to determine how much tax is payable, they work differently.
| Simple Assessment | Self Assessment |
| HMRC calculates your tax liability using information it already holds. | You are responsible for reporting your income, expenses, reliefs and allowances. |
| No tax return is normally required. | You must submit a Self Assessment tax return if required to do so. |
| HMRC decides who receives a Simple Assessment. | Taxpayers register for Self Assessment if they meet HMRC’s filing requirements. |
| Designed where HMRC already has enough information to calculate the tax due. | HMRC calculates the final liability based on the information submitted, although taxpayers can also calculate the amount themselves before filing. |
You cannot choose to receive a Simple Assessment HMRC decides whether it is appropriate in your circumstances.
When Are Simple Assessments Issued?
HMRC generally begins issuing Simple Assessments during the summer following the end of the tax year.
By this point, HMRC has received income information from employers, pension providers, the DWP and financial institutions.
Because information is received at different times, some taxpayers may receive more than one Simple Assessment for the same tax year if additional income is reported later.
What If You Disagree With Your Simple Assessment?
If you think your assessment is incorrect, you should contact HMRC as soon as possible.
Raise a Query
You normally have 60 days from the date the assessment was issued to raise a query by phone or in writing, explaining why you believe the calculation is incorrect.
Appeal
If you remain dissatisfied after HMRC responds, you can submit a written appeal within 30 days of HMRC’s final response.
Following the closure of a query, HMRC will normally issue a revised Simple Assessment where appropriate.
A query usually closes when:
- HMRC closes it manually; or
- Six months have passed since the query was raised.
Unlike a query, an appeal does not have an automatic closure date and remains open until it is resolved.
When Do You Need to Pay?
Payment deadlines broadly follow the Self Assessment timetable.
For the 2025/26 tax year:
- Assessment issued on or before 31 October 2026: Payment is due by 31 January 2027.
- Assessment issued after 31 October 2026: Payment must be made within three months of the date shown on the assessment letter.
If the figures appear correct, pay the amount due by the deadline to avoid interest and possible penalties.
Why Are More Simple Assessments Being Issued?
Although the Simple Assessment system has been available since 2017, HMRC has expanded its use significantly in recent years.
This is largely due to:
- Frozen Personal Allowance thresholds.
- Rising State Pension payments.
- Higher savings interest resulting in more taxable income.
- HMRC’s increased use of digital records and real-time reporting.
As HMRC receives more income information automatically, it can calculate tax liabilities without requiring many individuals to complete a full Self Assessment tax return.
State Pension and Simple Assessments
The State Pension Triple Lock guarantees that the State Pension increases each year by the highest of:
- Consumer Prices Index (CPI) inflation.
- Average earnings growth.
- 2.5%.
Because the Personal Allowance is currently frozen at £12,570 until April 2031, future increases to the full new State Pension are expected to push some pensioners above the tax-free threshold.
However, the Government has announced that pensioners whose only income is the full new State Pension will not be required to pay income tax before the end of the current Parliament (currently expected before 2030), subject to future legislation.
Practical Tip
Don’t ignore a Simple Assessment from HMRC.
Carefully check the figures against your own income records. If you believe the calculation is wrong, contact HMRC within the relevant time limits. If everything appears correct, make sure you pay by the deadline shown on the assessment to avoid unnecessary interest or penalties.
As HMRC continues to expand its use of digital reporting and real-time data, more taxpayers are likely to receive Simple Assessments instead of being asked to complete a full Self Assessment tax return.
Frequently Asked Questions (FAQs)
1. Do I need to file a Self Assessment tax return if I receive a Simple Assessment?
Usually not. A Simple Assessment is intended to replace a Self Assessment tax return where HMRC already has enough information to calculate your tax liability. However, HMRC may still require you to file a Self Assessment return if your circumstances change.
2. Can I request a Simple Assessment instead of Self Assessment?
No. HMRC decides whether a taxpayer receives a Simple Assessment based on the information it holds.
3. How long do I have to challenge a Simple Assessment?
You normally have 60 days from the date the assessment is issued to raise a query with HMRC.
4. What happens if I ignore a Simple Assessment?
If you fail to pay the tax due by the deadline, HMRC may charge interest and take action to recover the outstanding amount.
5. Can HMRC issue more than one Simple Assessment?
Yes. If HMRC receives additional information after issuing the original assessment, it may send a revised or additional Simple Assessment for the same tax year.
Need Help With Your HMRC Simple Assessment?
If you’ve received a Simple Assessment and are unsure whether it’s correct, professional advice can help you avoid paying the wrong amount of tax or missing important deadlines.
Our experienced tax advisers can review your HMRC calculation, explain your options, assist with queries or appeals, and help ensure you remain fully compliant with HMRC requirements. Contact us today for expert support.