Self-Assessment vs. Simple Assessment

What's Self-Assessment?

Self-Assessment is when you send HMRC a tax return yourself. It’s how you report all your income for the year, including anything that hasn’t been taxed already.

You'll usually need to use Self-Assessment if you:

• are self-employed and earned more than £1,000;
• earn more than £1,000 a year from renting out property or other untaxed income;
• are a higher or additional rate taxpayer claiming extra pension tax relief;
• need to pay Capital Gains Tax or the High Income Child Benefit Charge; or
• have other types of untaxed income.

You can check if you need to send a tax return on GOV.UK.

If you've never filed before, you need to register by 5 October. Once registered, you file your return and pay any tax owed by 31 January.

For the 2025/26 tax year, the deadline’s 31 January 2027. If you miss the deadline, HMRC can charge penalties and interest on overdue tax, so it's worth filing early.

What's a Simple Assessment?

Simple Assessment is when HMRC works out the tax for you and sends you a letter telling you how much you owe. The letter is called a PA302.

For example, it might apply if you receive income from:

• the State Pension;
• a workplace or personal pension;
• taxable state benefits (e.g. Carer's Allowance);
• untaxed interest or dividends; or
• other sources where tax hasn't been deducted correctly - if you owe tax, HMRC will send you a letter.

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Which one applies to me?

How to claim extra pension tax relief through Self-Assessment

If you pay higher rate (40%) or additional rate (45%) Income Tax, you might be entitled to extra pension tax relief on top of the basic rate that's added automatically.

Here's what to know:

• Basic rate tax relief - when you pay into a personal pension, your provider claims 20% basic rate tax relief from the government and adds it to your pot. For most basic rate taxpayers, every £100 you pay in, you’ll get a 25% tax top up - meaning HMRC adds £25, making it £125 in your pension. 
• Extra relief for higher rate taxpayers (40%) - you can claim a further 25% tax top up through your Self-Assessment tax return. This is on top of the 25% already added automatically.
• Extra relief for additional rate taxpayers (45%) - you can claim a further 31% tax top up through your Self-Assessment tax return. Again, this is on top of the automatic 25%.

For example, if you contribute £8,000 into your pension, with basic rate relief that becomes £10,000.

If you're a higher rate taxpayer, you can claim back a further £2,000 through Self-Assessment. If you're an additional rate taxpayer, you can claim back £2,500.

You'll need to include your gross contributions (the total amount in your pension including the 20% basic rate tax relief) when you complete your tax return.

You can claim by entering your gross pension contributions (the total amount including basic rate relief) in the ‘Pensions’ section of your Self-Assessment tax return. HMRC will then adjust your tax bill or send you a refund.

Use PensionBee’s Pension Tax Relief Calculator to see exactly how much tax relief you could claim based on your income and contributions.

Key things to remember

Understanding whether you need to file a Self-Assessment or if HMRC will send you a Simple Assessment instead helps you stay on top of your tax bill and make sure you claim any relief you're entitled to.

Here's what to remember:

• Self-Assessment - required if you're self-employed, or if your tax situation isn't fully handled through PAYE. This includes higher earners, people with significant untaxed income (like rental income, dividends above £500, or capital gains), or if you need to claim higher or additional rate pension tax relief.
• Simple Assessment - usually for more straightforward cases, often sent to pensioners whose State Pension exceeds their Personal Allowance, or people with smaller amounts of untaxed income (like interest) that can't be collected through PAYE.

It’s easy to mix up Self-Assessment and Simple Assessment. Knowing which one applies to you can help you meet any deadlines and make sure your tax’s collected correctly. If you’re ever unsure about your situation, it may help to double-check the latest guidance from HMRC.

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Risk warning

Please note that tax rules change regularly, and the actual tax benefits you receive will depend on your individual circumstances. If you’re not sure, please seek professional advice.

As always with investments, your capital is at risk. The value of your investment can go down as well as up, and you may get back less than you invest. This information should not be regarded as financial advice.

Last edited: 10-02-2026

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