Quick answer
You do not legally need an accountant if you are self-employed, but many sole traders use one to save time, claim every allowable expense and avoid penalties. A fixed-fee accountant often costs less than the tax relief they find.
Updated October 2026 · Figures based on 2025/26 rates
Filing your Self Assessment doesn’t have to be stressful. Let our qualified accountants handle everything — accurately and on time.
When you can manage alone
Simple income, few expenses, and confidence with HMRC’s online service. Good record-keeping software can make filing straightforward. If your records are tidy and you start before the autumn, HMRC’s online service walks you through the questions. The main risk is missing reliefs you did not know existed.
When an accountant helps
Multiple income types, rental income, dividends, CIS, a limited company, or complex expenses. They reduce errors and handle HMRC letters. If any of these apply, get a fixed written quote before the autumn rush so you can compare properly.
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Cost versus benefit
A fixed fee gives certainty. The value includes time saved, correct claims and help with future tax planning. Against that, set the hours you would spend doing it yourself and the cost of an error — a £100 late filing penalty alone can wipe out the saving from going DIY.
Questions to ask
Check qualifications, fixed pricing, what is included and how they handle HMRC enquiries. Ask who will actually prepare your return, how you will approve it before filing and what happens if HMRC writes to you afterwards.
Cost versus value over the year
It helps to think about the whole year rather than a single fee. Add up the hours you spend on bookkeeping, reading guidance and entering figures, and put a realistic value on that time. Then consider the cost of mistakes, such as an overlooked relief, a wrongly calculated payment on account or a late filing penalty. For some self-employed people the answer is still to do it themselves, and that is perfectly reasonable. For others, particularly those with several income streams or a growing business, a fixed fee removes uncertainty and frees up time to earn.
What the law requires and what it does not
There is no legal requirement for a self-employed person to use an accountant. You are responsible for registering with HMRC, keeping records, filing your return and paying the tax, and you can do all of that yourself. The deadlines are fixed: register by 5 October after the end of the tax year, and file online and pay by 31 January (31 October for a paper return). The real question is whether paying for help is worth it for you, and that depends on how complicated your affairs are, how confident you are with the figures and how much your time is worth.
When you can reasonably do it yourself
A straightforward sole trader with a single source of self-employed income, simple expenses, no employees and no other complications can often complete the return without help, particularly using HMRC’s free online service. If your income is low you may also be able to use the £1,000 trading allowance instead of listing expenses. The risks of going it alone are mainly time, mistakes and missed reliefs rather than anything unmanageable. Our guide to doing it yourself or using an accountant compares the options in more detail.
When an accountant is particularly worth considering
- Multiple income sources. Employment, rental income, dividends or foreign income alongside self-employment.
- Construction industry (CIS) work. Deductions, refunds and gross status add complexity.
- Growing profits. Income approaching £50,000 or £100,000 where tax rates and allowances change sharply.
- Making Tax Digital. From 6 April 2026 it applies to qualifying income above £50,000, then £30,000 from April 2027 and £20,000 from April 2028, bringing quarterly digital updates.
- Capital gains, pensions or child benefit charges that interact with your return.
- Late filing or an HMRC enquiry where professional handling matters.
Worked example: does an accountant pay for themselves?
This is an illustrative example, not a guarantee of savings. A sole trader earns profits of about £30,000 and files alone. Having an accountant review the figures uncovers £1,800 of legitimate expenses that were missed (for example part of a phone bill, professional subscriptions and home working costs). Those expenses reduce taxable profit, which saves income tax at 20% and Class 4 NI at 6%:
| Step | Working | Amount |
|---|---|---|
| Extra allowable expenses | Found on review | £1,800 |
| Income tax saved | £1,800 x 20% | £360 |
| Class 4 NI saved | £1,800 x 6% | £108 |
| Total tax saved | £360 + £108 | £468 |
| Fee at £199 + VAT | £199 x 1.20 | £238.80 |
| Net benefit | £468 – £238.80 | £229.20 |
Not every taxpayer will find savings like this, and some will have fewer missed claims. The value also lies in avoiding the cost of errors. A return filed late attracts a £100 penalty immediately, and further penalties build up after that, so having someone who manages the deadline can matter as much as the savings.
What to compare when you decide
Look at price, whether the fee is fixed, what is included, and whether the accountant is qualified and can answer questions during the year. Our guides on accountant costs and choosing an accountant walk through the questions to ask. You can also see what an accountant does for a sole trader.
Common mistakes
- Leaving everything until January and then rushing.
- Paying for an accountant but handing over incomplete records.
- Choosing on price alone without checking what is included.
- Assuming an accountant is only needed once profits are high.
- Not registering with HMRC in time, which an adviser would normally flag early.
Decision checklist
- List every source of income you have.
- Estimate how many hours the return takes you.
- Check whether Making Tax Digital will apply to you soon.
- Gather receipts, bank statements and CIS statements.
- Get a fixed quote before you commit.
Self Assessment Tax Return Accountants (SATR) offers a fixed fee from £199 + VAT, with qualified UK accountants preparing and filing your return online. Our sole trader service is a good place to start, and the article on how an accountant can save you tax gives more examples.
This article is general information, not personal tax advice.
Frequently asked questions
How much does an accountant cost for a sole trader?
Fixed fees often start around £199 plus VAT for a basic return, and rise with complexity. A straightforward sole trader return with SATR is £199 + VAT (£238.80).
Can I switch accountant later?
Yes. Your new accountant simply asks for authorisation from HMRC to act for you. Make sure your records are handed over and any outstanding fees are settled.
Is an accountant a tax-deductible expense?
Fees for preparing business accounts are generally an allowable expense for the business, but the cost of completing your personal tax return may be treated differently. Check current HMRC guidance or ask your accountant how to treat it.
Can I switch to an accountant part-way through the year?
Yes. You can appoint one at any time, although the earlier they see your records the more they can help with planning, expenses and avoiding surprises on the 31 January bill.
What if I have already missed a deadline?
File as soon as you can. A late return attracts a £100 penalty immediately, with further daily and percentage penalties building up, so quick action limits the cost.
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The Bottom Line
You do not legally need an accountant if you are self-employed, but the decision comes down to complexity, time and confidence. A fixed fee often pays for itself in found reliefs and avoided penalties — the £229.20 net benefit in the example above shows how.
If you would rather hand the whole job over, SATR prepares and files your Self Assessment for a fixed fee from £199 + VAT — done online by qualified UK accountants. Order online now or see our Self Assessment pricing.
