What is Simple Assessment?

A simple assessment is produced by HMRC and is also known as a form PA302. It’s typically issued to an individual who owes income tax from a previous tax year. HMRC uses simple assessment as a way to recover income tax in simple cases where an individual has not paid enough tax from PAYE income.

The system is designed to simplify the process for taxpayers who have underpaid and eliminates the need for individuals to submit a tax return to pay what they owe back to HMRC (Her Majesty’s Revenue and Customs).

A simple assessment calculation is based on data provided by employers, pension providers and other organisations like the department for work and pensions (DWP).

It’s vital to ensure all the information on your PA302 is accurate and that no essential details are overlooked by HMRC.

Why have I received a Simple Assessment letter?

HMRC issues simple assessment in cases where they believe you have not paid enough income tax from your PAYE income.

It’s usually not used if HMRC have to reconcile your income tax for more than one tax year.

The main reasons given by HMRC for sending a PA302 are:

• You owe income tax that cannot be directly deducted from your current earnings.
• You owe HMRC £3,000 or more in tax.
• You owe HMRC tax on state pension income.

A common reason for underpaying tax is when you have had more than one income source and an incorrect tax code has been used.

In this instance if you’ve not paid enough tax and HMRC can’t recover the shortfall automatically from your current income a PA302 may be generated.

How do I receive a Simple Assessment?

HMRC typically sends you a simple assessment PA302 through the post or via your personal tax account (or both).

Simple assessment is not used if you have already received a P800 tax calculation and the first letter requesting voluntary payment of income tax due.

It’s worth noting that an individual cannot register for simple assessment independently; it is used by HMRC at their discretion.

How do I check my Simple Assessment?

‍HMRC recommends that you review your simple assessment calculation diligently to ensure its accuracy before you make any payment.

A simple assessment review should check the income you’re taxed on (such as earnings from your job, pensions, or government benefits) and any income tax you have already paid.

You can use your physical P45 and P60 forms and/or find the same information online in your personal tax account.

The total earnings and tax deducted figures from your P45 and P60 forms can be used to calculate any tax you are still liable for and compare it to the simple assessment you have received.

Our income tax calculator is available to use as part of your checks by giving an estimation on how much tax you may owe in any of the last four tax years.

Appealing against a Simple Assessment

Initially you can write to HMRC or call them to explain the figures that you believe are incorrect.

HMRC should then write to you to confirm their decision. If you still don’t agree with their simple assessment demand you have the right to appeal.

HMRC asks for any appeal to be made within 60 days from the date the simple assessment was issued.

If no objection is raised within the 60 day period the assessment is automatically finalised by HMRC.

Simple Assessment deadlines

Payment for a simple assessment needs to be made within 3 months from the issue date if it’s received after 31st October.

Otherwise the payment should be made by 31 January of the year following the tax year for which the debt is owed.

Interest and penalties on Simple Assessments

HMRC has the authority and reserves the right to charge interest on underpaid tax and impose penalties for late tax payments in respect of simple assessments.

How to pay a Simple Assessment tax bill

Payment of your simple assessment tax bill can be made online through your personal tax account, via bank transfer or by posting a cheque.

When paying by cheque the reference number from the simple assessment letter must be written on the back of the cheque.

You can pay online without logging in to your personal tax account but you will need your payment reference number from your simple assessment letter.

What should I do if I can’t afford to pay a Simple Assessment tax bill?

If you can’t afford to pay a simple assessment tax demand within the timescales given you should let HMRC know as soon as you can.

In some cases HMRC might be able to help you pay what you owe back by agreeing to a payment plan over an agreed period of time.

Simple Assessment saves time but needs checked

The simple assessment is a significant step by the HMRC towards simplifying the income tax payment process by eliminating the need for individuals to submit a tax return for the taxable part of their income.

It has made the process of paying back underpaid tax through PAYE more straightforward and less time consuming but it’s not a perfect system meaning carrying out your own due diligence is important.

Key Takeaways

The points below summarise the deadlines and rules that apply to a Simple Assessment, based on HMRC’s published guidance.

• You can’t apply for one, and you can’t opt out of it either. HMRC issues a Simple Assessment automatically once it decides your tax can’t be collected through PAYE.
• It’s usually triggered by two things: State Pension income that exceeds your personal allowance, or underpaid tax (such as untaxed savings interest) that your tax code can’t recover.
• You have 60 days from the date on the letter to flag any figures you think are wrong — this is separate from a formal appeal.
• Payment is due by 31 January following the end of the tax year, or within 3 months of the letter’s date if HMRC sends it after 31 October.
• Interest builds up automatically on anything paid late. Unlike Self Assessment, HMRC currently does not charge separate late-payment penalties on Simple Assessment bills — but that could change, so it’s not worth relying on.
• If HMRC rejects your query, you get a further 30 days from their decision letter to lodge a formal appeal.

Simple Assessment Frequently Asked Questions

The answers below cover specific points on how a Simple Assessment is issued, checked, and paid, based on HMRC’s published rules.

Can HMRC send more than one Simple Assessment for the same tax year?
It’s become more common for some taxpayers to receive a second Simple Assessment for the same year. This typically happens when HMRC issues an initial calculation using data it already holds — pension or PAYE records, for instance — and then follows up once bank and building society interest information arrives later in the tax cycle.

The later letter reflects your full tax liability for the year rather than just the additional portion, which is why it’s worth comparing it against what you’ve already paid before settling it.

What’s the difference between a Simple Assessment and a P800?
Both are HMRC-calculated tax bills that don’t require a tax return, but they’re used differently: a P800 reconciles PAYE income where you’ve paid too much or too little through your tax code, while a Simple Assessment is used when the shortfall can’t be collected through PAYE at all — most commonly for state pension income or larger underpayments. You won’t get both for the same tax year.

Do I need to tell HMRC about income that isn’t shown on my Simple Assessment?
Yes. HMRC only includes income it already has third-party data for — from employers, pensions, banks, and the DWP — in a Simple Assessment.

Anything outside that, such as rental income or self-employment earnings, remains your responsibility to report separately, and the usual deadline for flagging it is 5 October after the end of the tax year.

Could my Simple Assessment be wrong because of an error from someone else, like an old employer or pension provider?
Yes — since the calculation is built entirely from data reported to HMRC by third parties, an error at the source (an employer, pension provider, or bank) will carry through into your assessment.

It’s still your responsibility to catch this, so checking the figures against your own records matters even if the mistake isn’t technically yours.

What happens if I pay two Simple Assessment letters for the same year in full?
This can result in an overpayment. Because a follow-up letter states your full liability for the year rather than an additional top-up amount, settling both letters in full effectively pays the total twice.

HMRC’s guidance confirms this doesn’t get corrected automatically — getting the money back means contacting them directly and asking for a refund.