Simple Assessment vs Self Assessment 2026/27: What's the Difference?
Simple Assessment is a bill HMRC calculates for you with no tax return required, unlike Self Assessment where you calculate and file your own return. Who gets each, and how payment works in 2026/27.
Two different routes to the same goal
Both Simple Assessment and Self Assessment exist to make sure the right amount of tax is paid on income that PAYE alone doesn't fully capture. The difference is entirely about who does the calculation — you, or HMRC.
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Under Self Assessment, the taxpayer is responsible for registering, gathering all relevant income and expense information, calculating the tax due (or using HMRC's online system, which does the arithmetic once the figures are entered), and filing a tax return by the deadline — 31 October for paper returns, 31 January for online returns, with payment also due by 31 January. This is the standard route for the self-employed, company directors, higher earners with complex income, and landlords, among others.
Simple Assessment: HMRC calculates and tells you
Under Simple Assessment, HMRC does the calculation itself, using PAYE data, State Pension records, and other information it already holds, and sends the taxpayer a bill — either by post or through their online personal tax account. There is no tax return to complete. The taxpayer's role is limited to checking the figures are correct and paying by the stated deadline.
Worked example: a pensioner on Simple Assessment
A retired person receives the full new State Pension (£241.30 a week, or £12,548 a year in 2026/27) plus a small additional private pension of £3,000 a year, which is taxed through PAYE.
- Total income: £12,548 + £3,000 = £15,548
- Personal Allowance: £12,570
- Taxable income: £15,548 − £12,570 = £2,978
- Tax at 20%: £2,978 × 20% ≈ £596
Because their private pension is small and taxed through a PAYE code that may not fully capture the interaction with the State Pension, HMRC may issue a Simple Assessment calculating and confirming the correct total tax due directly, rather than relying entirely on the pension provider's PAYE coding to get it exactly right.
What to do when you receive one
Check the income figures HMRC has used against your own records — bank statements, pension provider statements, P60s — since Simple Assessment relies on HMRC's data being accurate and complete. If something looks wrong (a missing pension, an outdated income figure), you can query or formally appeal within 60 days of the date on the assessment. If the figures are correct, pay by the deadline shown, which is typically 31 January following the end of the tax year, or a set number of days after issue if sent later in the year.
self-employed-tax-ukBottom line
Simple Assessment removes the burden of filing a tax return for people with otherwise straightforward tax affairs that PAYE alone can't quite handle — most commonly pensioners. It shifts the calculation work to HMRC, but not the responsibility to check the figures and pay on time, so treating a Simple Assessment letter with the same care as a Self Assessment bill remains important.
Sources
- GOV.UK: Simple Assessment
- GOV.UK: Self Assessment tax returns
Frequently asked questions
What is the main difference between Simple Assessment and Self Assessment?
With Self Assessment, you calculate (or your accountant calculates) your own tax liability and submit a tax return declaring your income. With Simple Assessment, HMRC calculates the tax bill itself, using information it already holds, and simply sends you the amount to pay — there is no tax return to complete.
Who typically gets a Simple Assessment instead of Self Assessment?
Simple Assessment is commonly used for people whose tax situation is straightforward but doesn't fit neatly into standard PAYE — for example, some pensioners whose State Pension alone exceeds their Personal Allowance, or people who owe tax that can't be collected through a tax code adjustment.
Do I need to do anything if I receive a Simple Assessment?
You need to check the figures HMRC has used are correct and pay the bill by the deadline shown — usually by 31 January following the tax year the assessment covers, or within a set number of days if the assessment is issued late in the year. You don't calculate anything yourself, but you are responsible for spotting and querying any errors.
What if I disagree with a Simple Assessment?
You can query or appeal a Simple Assessment within 60 days of receiving it if you believe the figures are wrong, for example if HMRC has used out-of-date income information.
Can I be moved from Self Assessment onto Simple Assessment?
Yes, HMRC can move some taxpayers from Self Assessment to Simple Assessment if their circumstances become straightforward enough, most commonly for pensioners whose only income sources are the State Pension and one or two other simple, already-reported income streams.
Does Simple Assessment mean I never need to file Self Assessment again?
Not necessarily — if your circumstances become more complex again, such as starting self-employment or gaining rental income, HMRC can require you to register for and complete Self Assessment instead, even after previously being on Simple Assessment.
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