Dealing with a Simple Assessment letter | Outsourced Financial | Outsourced Bookkeeping Services

olivia26264
Jul 3
2 min read

Simple Assessment is used by HMRC to collect tax underpayments from taxpayers with straightforward tax affairs. It removes the need for the taxpayer to complete a Self Assessment tax return.

HMRC will issue a Simple Assessment where there is an underpayment of tax which cannot be collected through PAYE. Each year HMRC undertake a PAYE reconciliation process and issue a P800 calculation. Where this shows that tax is owing which cannot be recovered through PAYE, they may issue a Simple Assessment. A Simple Assessment letter will be sent by post or issued to the taxpayer’s personal tax account if they have one. The letter will show the taxpayer’s taxable income, tax that has been paid and the amount that is owed.

Check if it is correct

It is important to check that the figures in the Simple Assessment are correct – HMRC can, and do, make mistakes. You should check the amounts shown in the Simple Assessment against your P60, bank statements, letters from the Department for Work and Pensions, and similar. If you do not understand the figures, it is prudent to take advice.

If you think the calculation is wrong, you should tell HMRC, either by writing to them or by calling them. You must do this within 60 days of the date on the letter. You should tell HMRC which figures you think are wrong and what you think they should be. If HMRC agree with you, they will send you a new Simple Assessment with the revised figures. If they think their figures are correct, they will send you a decision letter explaining why. If you still do not agree with them, you can appeal. This must be done within 30 days of the date on which the decision letter was issued.

Payment must still be made on time while the appeal is dealt with unless HMRC instruct otherwise.

Paying your Simple Assessment

Tax owed under Simple Assessment can be paid online, by bank transfer or by cheque. The date by which payment must be made depends on the date on which the Simple Assessment letter was received. Where the letter for the 2024/25 tax year is received before 31 October 2025, payment must be made by 31 January 2026. Where the letter for 2024/25 is not received until after 31 October 2025, payment must be made no later than three months from the date on the Simple Assessment letter.

Interest will be charged on payments made late.