Many people find the Self Assessment tax return confusing and stressful. It brings to mind searches for lost paperwork, looming deadlines, and the fear of getting something wrong. But the truth is, not everyone needs to file one.
So, how do you know if you do need to do a self assessment? Let’s break it down in this blog so you can understand whether you’re on HMRC’s radar, and what to do if you are.
What is a Self Assessment tax return?
Self Assessment is HMRC’s system for collecting Income Tax from people whose tax isn’t automatically deducted from their wages, pensions, or savings.
If you’re an employee, your employer usually deducts tax through PAYE (Pay As You Earn). But if you earn income outside PAYE, HMRC needs you to declare it by filing a tax return.
A Self Assessment tax return tells HMRC:
- How much you earned (from work, property, investments, etc.)
- What expenses can you claim (if you’re self-employed or a landlord)
- Whether you’ve already paid some tax (e.g., via PAYE or bank interest deductions)
- What tax you still owe — or whether you’re due a refund
Who actually needs to file a Self Assessment?
For the 2025/26 tax year, you may need to file a Self Assessment tax return if:
- You are a sole trader and your income (before expenses) is more than the £1,000 trading allowance.
- You are a partner in a business.
- You earn property income above the set limits.
- You need to claim work-related expenses of more than £2,500 in a tax year.
- You need to pay Capital Gains Tax that hasn’t already been settled during the year.
- You serve as a minister of religion (any faith or denomination).
- You earn income from a trust or estate of someone who has passed away, and more tax is owed.
- You have foreign income. (The exception is if it’s only dividend income and, together with any UK dividends, it is less than the dividend allowance.)
- You want to claim relief under a double tax agreement or claim the remittance basis (where it does not apply automatically).
- You live outside the UK but still have a taxable UK income.
- You have savings income of £10,000 or more (not counting ISA savings).
- You have dividend income of £10,000 or more (not counting ISA dividends).
- You have untaxed income of £2,500 or more.
- Your total taxable income before tax is £150,000 or more.
- You or your partner needs to pay the High Income Child Benefit Charge.
This is not a full list. HMRC may ask you to complete a Self Assessment for other reasons too, such as to collect unpaid tax.
Who usually doesn’t need to file?
If you’re an employee and all your income is taxed under PAYE, you probably don’t need to do a Self Assessment.
You’re unlikely to file if:
- You only receive wages or a pension taxed at source.
- Your savings and investments are small, and tax is already deducted.
- You don’t earn any extra income outside your job.
That said, sometimes HMRC asks people to file even if their circumstances look simple. If you’ve received a notice from HMRC, don’t ignore it — you must either file or formally tell them you don’t need to.
How do you check if you need to file?
The easiest way is to use HMRC’s online checker tool on GOV.UK. It asks you a few questions and tells you whether you’re required to complete a return.
You can also phone HMRC directly if you’re unsure. It’s better to double-check than risk penalties for missing a filing requirement.
What happens if you do need to file?
If you’ve confirmed you need to do a Self Assessment, here’s what to expect:
- Register with HMRC – If you’re new to Self Assessment (say you’ve just started freelancing), you’ll need to register by 5 October of the year following the end of the tax year, eg, 5 October 2025 for the tax year 2024/25. HMRC then sends you a Unique Taxpayer Reference (UTR).
- Keep records – Track your income and expenses throughout the year. This makes filing much easier.
- Submit the return – You can file online or by paper (though paper deadlines are earlier).
- Pay what you owe – The deadline to file your return online and pay any tax owed is 31 January after the end of the tax year.
For example, for the tax year running from 6 April 2024 to 5 April 2025, your filing and payment deadline is 31 January 2026.
What if you don’t file when you should?
Penalties can add up fast:
- £100 if you miss the deadline (even if you owe no tax).
- Daily fines if you’re more than 3 months late.
- Further penalties after 6 and 12 months.
- Interest on any late tax owed.
In short, if HMRC expects a return from you, it’s best not to ignore it.
Why you might want to file even if you don’t have to
Some people choose to file voluntarily. Here’s why:
- To claim tax reliefs – e.g., pension contributions, charitable donations, or work expenses.
- To claim expenses as a landlord or self-employed person, even if you’re under the threshold.
- To prove income, mortgage lenders and visa applications often require a Self Assessment record.
So even if HMRC doesn’t demand it, filing might work in your favour.
Tips for first-time filers
If you discover you need to file, don’t panic. Here are a few tips to make the process smoother:
- Register early – Getting your UTR can take a few weeks.
- Go digital – Online filing is faster and calculates your tax instantly.
- Use software or an accountant – Helps track records and claim all entitlements.
- File early – Avoid last-minute stress and give yourself time to plan for the bill.
Key deadlines to remember
- 5 October – Register for Self Assessment (new filers)
- 31 October – Paper tax returns
- 31 January – Online returns and payment
Conclusion
So, do you need to do a Self Assessment?
The answer depends on your situation. If all your income is taxed through PAYE and you have no other earnings, probably not. But if you’re self-employed, a landlord, a high earner, or have untaxed income, you probably do.
When in doubt, check with HMRC or a qualified accountant. Filing when you don’t need to won’t hurt, but missing one when you should can be costly.
Not sure where you stand? Contact us and we’ll help you get it sorted.
