HMRC is expected to send around 1.8 million Simple Assessment letters relating to the 2025/26 tax year, a significant increase on previous years.
If you receive one, it’s important not to ignore it. The letter outlines tax that HMRC believes you owe and, while the calculation may be correct, it’s worth checking the figures carefully before making any payment.
Simple Assessments are issued when HMRC believes income tax is due but cannot be collected through Pay As You Earn (PAYE). Rather than requiring an individual to complete a Self Assessment tax return, HMRC calculates the tax owed and issues a notice directly.
One of the reasons for the increase is the continued freeze of the personal allowance at £12,570, meaning more people are finding themselves with tax to pay as pensions, savings income and earnings rise.
Who could receive a Simple Assessment letter?
Simple Assessment is commonly used where individuals have income that has not been fully taxed through PAYE, including:
- State Pension income
- Interest from banks and building societies
- Other sources of income known to HMRC where additional tax may be due
HMRC uses information from employers, pension providers, financial institutions and government departments when calculating any tax liability.
Why are more letters being issued?
The number of Simple Assessment notices has increased significantly in recent years.
HMRC issued approximately 675,000 letters for the 2021/22 tax year, and for 2025/26, that figure is expected to reach 1.8 million.
With the personal allowance currently frozen until at least April 2031 under existing plans, increasing numbers of taxpayers may receive Simple Assessment notices in future years.
This is particularly relevant for pensioners, many of whom may receive a Simple Assessment for the first time as pension income increases and exceeds available tax allowances.
When will letters be sent?
HMRC began issuing the first batch of letters during Summer 2026, with notices being sent to both working-age taxpayers and pensioners.
A second batch of letters relating to bank and building society interest is expected to be issued between October and December 2026.
Some taxpayers may receive more than one Simple Assessment letter for the same tax year, particularly where HMRC receives updated information about savings interest or other sources of income.
What should taxpayers do?
If you receive a Simple Assessment letter, it is important to review it carefully and check that the information used by HMRC is accurate.
You should:
- Compare the figures against your own records
- Check any pension income, savings interest and other income included in the calculation
- Contact HMRC if you believe any information is incorrect
- Ask for the assessment to be withdrawn if you already complete a Self Assessment tax return
HMRC is encouraging taxpayers not to ignore these letters and to raise any queries as soon as possible.
When does the tax need to be paid?
The payment deadline for most 2025/26 Simple Assessment tax bills is 31 January 2027, unless a different date is shown on the notice.
If you are unable to pay the amount due in full, you may be able to agree a Time to Pay arrangement with HMRC.
Don’t ignore the letter
Receiving an unexpected tax bill can be concerning, particularly if you’re unsure how HMRC has arrived at the figures. If you think your simple assessment is wrong you have 60 days from the date of the letter to query it with HMRC.
Checking the assessment as soon as possible can help identify any errors and avoid unnecessary interest or penalties.
Get in touch
If you’ve received a Simple Assessment letter and would like reassurance that the calculation is correct, our tax team is here to help.
To discuss your situation, contact PM+M by emailing enquiries@pmm.co.uk.
