Do I need an accountant for Self Assessment?

The short answer

No. GOV.UK presents an accountant as a choice, not a requirement. You can send a tax return yourself, either by submitting an online return or sending a paper return, and HMRC's own online service is open to you if you are self-employed, or if you are not self-employed but still send a tax return, for example because you receive income from renting out a property. Separately, you can authorise an agent, such as an accountant or tax adviser, to manage your tax affairs.

Before deciding who should prepare a return, check that you need to send one at all — HMRC has a tool for that. If you do, the real question is how much of the work you are comfortable doing. Doing it yourself is realistic for a straightforward return: the online return has help text throughout, and HMRC publishes guidance on each section. An accountant is more likely to be worth paying for if HMRC's online service does not cover your case, if you are a partner in a partnership, if your accounting period does not line up with the tax year, or if you are unsure what to include and would rather not find out the hard way.

Last checked 23 October 2026 · GOV.UK sources

What to weigh

Do you need to send a return at all?

GOV.UK says you must send a tax return if, in the last tax year (6 April to 5 April), you were self-employed as a sole trader and earned more than £1,000 before taking off anything you can claim tax relief on; you were a partner in a business partnership; you had to pay Capital Gains Tax; you had to pay the High Income Child Benefit Charge and do not pay it through PAYE; or you are an off-payroll worker repaying a student or postgraduate loan. You may also need to send one if you have untaxed income, such as rent, tips and commission, savings interest, dividends or foreign income. And if HMRC wrote to you asking for a return, you must send it by the deadline on the letter. If none of these fits, use HMRC's 'check if you need to send a tax return' tool before paying anyone to prepare one: you may not need a return, let alone an accountant.

Does HMRC's online service cover your return?

GOV.UK says you cannot use HMRC's online service to file for a partnership; for a trust or an estate; if you lived abroad as a non-resident; to report multiple 'chargeable event gains', for example from life insurance; or if you get income from a trust, you are a Lloyd's underwriter or a religious minister. In those cases you use commercial software or download or request other forms instead. If you are filing for the first time you must register for Self Assessment before using the service, and you'll need your Unique Taxpayer Reference (UTR). You do not have to complete the return in one go: you can save your entry and go back to it later.

How much help would you need with the content?

GOV.UK says there is help text throughout the online tax return that gives information on completing each section, and HMRC publishes guidance on the sections of the return, including self-employment, employment, pensions, other UK income, property and capital gains. HMRC also offers email updates, videos and webinars, including for people filling in a return for the first time, and a digital assistant you can ask questions about Self Assessment. If you have read the guidance for your sections and still cannot tell what goes where, that is a fair sign that paying someone is worth it.

Do you know your profit for the whole tax year in time?

GOV.UK says you might not, for example if your accounting period ends at a different time to the end of the tax year, or is different to your basis period, or you are waiting for a valuation. You still need to send a return: you work out what your profit is likely to be (provisional figures), tell HMRC you have used them, and change your return once you know, within 12 months of the Self Assessment deadline. If more tax is due you pay interest on the difference, worked out from the original due date. This is one of the situations where an accountant's help is most likely to pay its way.

Can you meet the deadlines?

For the 2025 to 2026 tax year, GOV.UK says HMRC must receive a paper return by 11:59pm on 31 October 2026 and an online return by 11:59pm on 31 January 2027, and you must pay the tax you owe by 11:59pm on 31 January 2027. If you need to complete a return for that year and have either not sent one before, or registered before but did not need to send one for the 2024 to 2025 tax year, you had to tell HMRC by 5 October 2026; if you register after that, HMRC will give you a different deadline to send your return, but the payment date stays the same. You'll get a penalty if you send your return late or pay your tax bill late — the Self Assessment deadlines guide sets out the amounts.

The options, and who each is not for

Filing it yourself, online or on paper

Suits:

Someone whose return HMRC's online service covers: self-employed, or not self-employed but sending a return, for example because of income from renting out a property.
A return with only a few income sources, each covered by HMRC's section guidance.
Anyone willing to read the guidance for their sections, and to start early enough to save and come back to it.

Not for:

A partnership, a trust or an estate, a non-resident, or anyone else HMRC's online service does not cover: GOV.UK points you to commercial software or paper forms instead, which is more to get right on your own.
Someone whose accounting period does not line up with the tax year and who would need provisional figures and a later amendment.
Anyone hoping that finding HMRC's online system difficult will excuse a late return. GOV.UK lists 'you found the HMRC online system too difficult to use' among the things that will not be accepted as a reasonable excuse, and the same goes for a mistake on your tax return.

Help from a friend, relative or voluntary organisation

Suits:

Someone who mainly needs help with the forms. GOV.UK says you can authorise a friend, relative or voluntary organisation as an 'intermediary' to talk to HMRC, answer questions on your behalf and help you fill in forms. You authorise one by writing to HMRC.
Short-term help with Self Assessment: GOV.UK says you can call HMRC with the person who is helping you, who must be with you when you call.

Not for:

Someone who wants the helper to file online for them. An intermediary will not have access to your tax online, and a 'trusted helper' — the separate arrangement for managing your tax online — cannot use that service to help you with your Self Assessment.

Paying an accountant or tax adviser

Suits:

A partnership, or any return HMRC's online service does not cover.
A year with provisional figures, several kinds of income, or capital gains you are not confident reporting.
Anyone who would rather pay than learn the return, or who wants HMRC's letters handled for them: GOV.UK says that if you have to fill in a Self Assessment tax return, HMRC will send all correspondence to the person you've authorised, except tax bills or refunds.

Not for:

Someone who may not need to send a return at all: check first.
A simple return that HMRC's online service covers and that you are comfortable completing with its help text and section guidance.
Anyone who will not keep their records during the year: whoever prepares the return works from the figures you give them.

Frequently asked

Can I file Self Assessment without commercial software?

Yes, unless your case is one HMRC's online service does not cover. GOV.UK says you can file your Self Assessment tax return online through HMRC if you are self-employed, or not self-employed but still send a tax return. It cannot be used for a partnership, a trust or an estate, if you lived abroad as a non-resident, to report multiple chargeable event gains, or if you get income from a trust, are a Lloyd's underwriter or a religious minister; for those, GOV.UK says to use commercial software or download or request other forms instead.

If my accountant files late, do I still get the penalty?

GOV.UK says that if you have a reasonable excuse, you can appeal against a penalty. GOV.UK lists 'you relied on someone else to send your return, and they did not' among the examples of what may count as a reasonable excuse, and says you must send your return or payment as soon as you're able to. Whether HMRC accepts it in your case is for HMRC to decide.

What does an accountant need from me before they can deal with HMRC?

GOV.UK says a paid agent can be a professional accountant or tax adviser, they must meet HMRC's standard for agents, and you must authorise your agent before they can deal with HMRC on your behalf — they will tell you how to do this. Depending on what you've authorised them to do, they'll be able to deal with your tax affairs, for example submitting your Self Assessment tax return.

I have a health condition that makes this hard. What can I do?

GOV.UK says that if your health condition or personal circumstances make it difficult when you contact HMRC, you can appoint someone to fill in and send your tax return, for example an accountant, friend or relative, or get help from HMRC's extra support team.

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Worth saying: if your affairs are very simple, you may not need an accountant at all — this is for when you’d rather someone else handled it.

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Sources

Every deadline, penalty and rule on this page is taken from these GOV.UK pages, read on 23 October 2026.

This page is general information based on GOV.UK published guidance, not tax or legal advice. Your own position can differ. Check the GOV.UK sources above and speak to a qualified accountant before making decisions about your own tax affairs.