Do You Need to Do Self Assessment? Easy Checks to Find Out

7 November, 2025 · 6 min read

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If you’ve ever wondered “Do I need to file a Self Assessment?” you’re far from alone. The world of Self Assessment can be confusing. Thankfully, ANNA is here to help.

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The UK Self Assessment system is how HMRC collects Income Tax from people whose income isn’t fully taxed through PAYE. That means it affects millions of self-employed people, landlords, directors, and anyone with untaxed income from other sources. Around one in four people in Britain have to file a Self Assessment - is that you?

This guide includes a handy Self Assessment checker to help you quickly work out whether you need to file - we’ll also tell you everything you need to know about who has to file, who doesn’t, and how to stay on the right side of HMRC (for example, by using ANNA to keep track of all your transactions and file your Self Assessment).

Self Assessment checker

Our quick Self Assessment Checker questionnaire below is designed to make things easy. Just answer a few yes/no questions, and you’ll see whether you need to submit a return.

Before you start, here’s a quick note about the UK tax year:

The UK tax year runs from 6 April to 5 April the following year. For example, the 2024/25 tax year runs from 6 April 2024 to 5 April 2025, and the online Self Assessment deadline for that year is 31 January 2026.

When you answer the questions below, think about your income, work, and finances during that specific tax year, not the calendar year.

Self Assessment checker - just answer Yes or No

Answer Yes or No to each question. If you answer Yes to any question, you probably need to file. It’s as simple as that. Thankfully, you can use ANNA’s Self Assessment Tax Checker.

Self Assessment Tax Checker

Question	Do you need to file?
Did HMRC send you a “notice to file” (a letter telling you to send a Self Assessment)?	Yes ✅	No ❌
If Yes: You have to file - unless HMRC withdraws the notice.
Were you self-employed (a sole trader) during the tax year and was your gross - that means before tax - income over £1,000?	Yes ✅	No ❌
If Yes: You have to register and file. If your self-employment income was £1,000 or less you may not need to tell HMRC because there’s a £1000 trading allowance.
Were you a partner in a business partnership (including LLP) at any point in the tax year?	Yes ✅	No ❌
If Yes: If you’re in a business partnership you have to file and the partnership also has to submit a partnership return.
Are you a company director who was paid in dividends or any other untaxed income?	Yes ✅	No ❌
If Yes: You probably need to file – directors occasionally don’t need to file if all income is taxed under PAYE, but dividends/untaxed income will trigger a filing.
Do you have kids - and is your adjusted net income over the High Income Child Benefit Charge threshold (e.g., you or your partner received Child Benefit and your income is above the threshold)?	Yes ✅	No ❌
If Yes: You have to file to report and pay the HICBC. It’s worth noting that: thresholds changed recently so check HMRC for the tax year that applies
Did you have untaxed income (outside PAYE) such as: lots of savings interest, dividends above the dividend allowance, other untaxed pensions or taxable state benefits, or other income HMRC doesn’t collect through PAYE?	Yes ✅	No ❌
If Yes: You may need to file to report and pay tax on that income.
Did you have any rental income from property and either: (a) your gross property income was more than £1,000, or (b) you want to claim allowable expenses, losses, or are using Rent-a-Room?	Yes ✅	No ❌
If Yes: You likely need to file. (There is a £1,000 property allowance with similar rules to the trading allowance.)
Did you make capital gains (for example you sold shares, crypto, or property) above the Annual Exempt Amount, or did you need to report a UK property disposal within 60 days?	Yes ✅	No ❌
If Yes: You have to report Capital Gains. Include them on Self Assessment if they’re reportable. (UK property disposals have separate 60-day reporting as well.)
Did you have foreign income (overseas interest, dividends, foreign rental, or overseas employment income) that’s taxable in the UK, or did you claim under the remittance basis?	Yes ✅	No ❌
If Yes: You may need to file a Self Assessment to declare foreign income or claim double taxation relief.
Do you fall into any other special categories (trustee, estate, minister of religion, Lloyd’s underwriter, had a pension annual allowance charge or other chargeable event)?	Yes ✅	No ❌
If Yes: Those are specific statutory triggers for filing, so you’ll need to file.
If you answered No to all questions, you don’t have to file a Self Assessment Tax Return. Phew!

Who needs to file a Self Assessment tax return – a closer look

With the questionnaire done, we thought we’d take a deeper dive into exactly who has to file a Self Assessment.

The self-employed and sole traders

If you were self-employed during the tax year and earned more than £1,000 before expenses, you have to register and file. Even if you earned less, you might still want to file if you want to claim expenses or record a loss for future years.

Some examples:

You’re a self-employed plumber and earned £57,000 before tax. Do you have to file a Self Assessment tax return? Yes.

You sell some old comics on eBay and make £750 before tax. Do you have to file a Self Assessment tax return? Probably not.

Side gigs and freelancing

Casual income, side hustles, or one-off freelance jobs do all count as self-employment income.

But you can use the £1,000 trading allowance instead of filing a return as long as your total income from self-employment stays under that amount and you’re not claiming expenses.

Basically, if your side hustle earned you less than £1000 (e.g. selling clothes on Vinted) then you almost certainly don’t have to do a Self Assessment.

Partners in a business partnership

If you’re a partner, you have to file your own Self Assessment return and the partnership itself has to submit a partnership return (yes, it seems like a faff, but ANNA can help!). This includes LLPs and salaried partners in professional firms.

(A business partnership is a legal arrangement where two or more people run a business together, sharing the profits, losses, and responsibility for the business’s debts and decisions.)

Company directors

But not all directors need to file! Directors only need to file if they have untaxed income (like dividends or benefits not handled by PAYE).

High income thresholds

You’ll need to file if your income exceeds £100,000 or if you (or your partner) get Child Benefit and your adjusted net income is over £50,000, triggering the High Income Child Benefit Charge (HICBC).

Untaxed income: savings interest and dividends

If your savings or dividend income go over your allowances (the Personal Savings Allowance, Starting Rate for Savings, or Dividend Allowance) you may need to file to pay tax on the excess.

Savings interest includes interest from a bank or building society savings account, interest from credit union savings, Interest from National Savings & Investments (NS&I) products (unless they’re tax-free, like Premium Bond prizes).

Banks and building societies used to deduct taxes automatically but they don’t do that anymore, so the interest counts as untaxed income - you may need to declare it if it’s over your Personal Savings Allowance (currently £1,000 for basic-rate taxpayers, £500 for higher-rate).

A quick reminder on dividends! They’re payments you get if you own shares in a company. For example:

Dividends from shares you hold personally (e.g. Barclays, Tesco, or other listed companies)
Dividends from your own limited company (if you’re a shareholder-director)
Dividends from UK or overseas investments

These are paid without the tax deducted, so they’re untaxed income when you receive them. You only pay tax on dividends above your Dividend Allowance (£500 for 2024/25).

Rental and property income (landlords)

If you rent out property, you’ll probably need to file if:

Your rental income exceeds £1,000 (the property allowance), or
You’re claiming expenses, reporting a loss, or using the Rent-a-Room Scheme

Capital gains and property disposals

A capital gain is the profit you make when you sell or dispose of something valuable, like shares, crypto, or property, for more than you paid for it.

You have to file a Self Assessment if you’ve made capital gains above the Annual Exempt Amount (currently £3000) If you sold a UK property and reported it within 60 days, you still need to include it in your annual Self Assessment.

So if you bought shares for £3000 and sold them for £7500, that would trigger Capital Gains Tax on the total above the exempt amount (so you made £4500 profit, and you’d be taxed on the £1500 above the threshold).

Foreign income, non-domicile and non-resident cases

If you earn income abroad – like overseas interest, dividends, or rent – or claim the remittance basis, you’ll also need to file. The same applies if you’re a non-resident landlord or want to claim double tax relief.

Other reasons HMRC may ask for a tax return

Less common cases include trustees and estates, ministers of religion, Lloyd’s underwriters, pension or MPAA excesses, or chargeable events on life policies.

So, who usually doesn’t need to file?

Employees and pensioners with no untaxed income

If all your income is taxed through PAYE and you have no other taxable income, you usually don’t need to file a Self Assessment.

So, for example, if you work in an office 9-5 and don’t have a side hustle, it’s unlikely you’ll have to file a Self Assessment return.

Small side income within allowances

If your side gig or property income is under the £1,000 trading or property allowance and you’re not claiming expenses or losses, you don’t need to file.

When HMRC collects via PAYE or Simple Assessment

Sometimes HMRC adjusts your tax code or issues a Simple Assessment instead of requiring a return. If this applies, you’re covered.

If HMRC has not asked you to file

You only need to file if you meet the criteria or receive a notice to file. If unsure, use the HMRC Self Assessment checker or call HMRC to confirm.

No longer need to file a Self Assessment?

Ask HMRC to stop sending returns

If you no longer meet the criteria, tell HMRC via your online account or by phone/post that you want to leave Self Assessment.

So if you’ve been freelancing for years but now have a PAYE job, do let HMRC know, so they no longer expect you to file a Self Assessment.

If HMRC has already issued a notice, you must still file unless they formally withdraw it. You can request withdrawal if you genuinely don’t need to file.

Stopping self-employment or property letting

On your final return, tick the box to show you’ve stopped trading or renting, and inform HMRC so they can close your record.

Keep records and monitor future years

Keep your income records safely (for example by using ANNA) and re-check your status every year – thresholds and personal circumstances can change.

Check your Self Assessment status online

HMRC Personal Tax Account and SA online

Log in to your HMRC Personal Tax Account to check your Self Assessment status, see returns due, submitted returns, and penalties.

Find your UTR and Government Gateway details

You’ll need your UTR (Unique Taxpayer Reference) and Government Gateway ID to sign in. You can recover these online if you’ve misplaced them.

HMRC’s “Check if you need to send a Self Assessment” tool

HMRC’s own Self Assessment checker is quick and reliable. It’s great for confirming your result if you’re unsure.

View payments, statements and deadlines

From your account, you can check what you owe, your payments on account, and your payment history.

What you need to file a Self Assessment tax return

Category	Required documents/details
IDs and access codes	You’ll need your UTR, National Insurance number, Government Gateway ID, and activation code if filing for the first time.
Employment income and benefits	Gather your P60, P45, P11D, and details of any taxable benefits or tips.
Self-employment income and expenses	Keep your invoices, bank statements, and records of allowable expenses. Decide whether to use cash basis or traditional accounting.
Rental income and expenses	Include rent you’ve been paid, letting agent statements, and deductible costs (mortgage interest, repairs, insurance).
Savings, investments and dividends	You’ll need statements or vouchers showing interest and dividends received – but not ISAs, which are tax-free.
Capital gains	Keep records of asset sales, purchase and disposal dates, costs, and reliefs claimed.
Pensions, benefits and other adjustments	Include details of any private or state pensions, student loans, Gift Aid, and Marriage Allowance.

Deadlines, registration and payments

Registering for Self Assessment

You must register by 5 October after the end of the tax year you started earning untaxed income. Use form SA1 or register as self-employed.

Filing deadlines and amendments

Paper returns: 31 October
Online returns: 31 January
You can amend a return for up to 12 months after submission.

Payment deadlines and Payments on Account

Payments are due by 31 January (balancing payment) and possibly 31 July (Payments on Account) if your tax bill exceeds £1,000.

Penalties and interest

Late filing leads to automatic £100 fines, daily penalties after three months, and interest on unpaid tax.

Special situations and edge cases

CIS subcontractors: Usually file to reclaim tax deducted.
Cryptoassets and online platforms: Report capital gains or trading income above allowances.
Non-residents: File if you earn UK income or want to claim relief.
HICBC: Applies if income exceeds £50,000 and Child Benefit is received.
Simple Assessment: Sometimes replaces SA for straightforward cases.

How HMRC checks Self Assessment returns

HMRC matches data from banks, employers, property records, and digital platforms.

Most checks are automated, but they can open compliance enquiries if figures don’t add up. Good record-keeping reduces risk.

If you need to file: your next steps

Set aside tax funds regularly and check whether you’ll owe Payments on Account. If cash flow is tight, HMRC offers a Time to Pay plan.

If you don’t need to file: staying compliant

You can often have small amounts of untaxed income collected through PAYE via a tax code adjustment. Keep your records and re-check each year if anything changes.

How ANNA can help

If you do need to file a Self Assessment, ANNA can help. Our Self Assessment tool and MTD Self Assessment tool mean that however you file, it’s simple and straightforward. You connect your bank or business account to ANNA, and it pulls in all your transactions. You answer a few basic questions and your income and allowable expenses are calculated.