Every year, millions of UK taxpayers face the Self Assessment deadline with the same dilemma: should I file my tax return myself or hire an accountant? It’s a legitimate question, especially when you’re trying to keep costs down or your tax affairs seem straightforward.
The truth is, you do not legally need an accountant for Self Assessment. HMRC’s online system is designed so individuals can complete it themselves. However, whether you should use one depends on your specific circumstances, how complex your finances are, and how you value your time compared to the savings and peace of mind an accountant can provide.
This guide from Flux Accounting & Taxation will help you make an informed decision based on your situation, showing you when DIY makes sense and when professional help pays for itself many times over.
When You Can Probably Do It Yourself
Self Assessment isn’t inherently difficult if your tax situation is straightforward. Many people successfully file their own returns every year without professional help. You might be fine filing yourself if:
Your situation is simple: You have employment income from one job, perhaps some bank interest or small dividends, and nothing else complicated. The online form guides you through step by step, and you can complete it in 30-60 minutes.
You’re comfortable with numbers and forms: If you don’t find financial paperwork intimidating and you’re willing to spend time understanding the questions, HMRC’s system is reasonably user-friendly.
You have minimal deductible expenses: If you’re not claiming business expenses, capital allowances, or complex reliefs, there’s less room for error or optimisation.
You have time to learn: If you’re prepared to read HMRC guidance, watch tutorials, and work through the form carefully, you can absolutely do it yourself.
Your tax is simple employment-based: Basic PAYE income with perhaps a small side hustle earning under £1,000 (where the trading allowance applies) is manageable for most people.
The key advantage of DIY is cost—it’s free except for your time. For someone with genuinely simple affairs, paying £150-£300 for an accountant might feel unnecessary.
When You Should Seriously Consider an Accountant for Self Assessment
However, many people overestimate how “simple” their tax situation is. Here’s when professional help becomes valuable or essential:
1. You’re Self-Employed or Run a Business
This is the big one. Self-employment adds significant complexity with allowable expenses, capital allowances, accounting methods, and strategic decisions that materially affect your tax bill.
Most self-employed people who file themselves either overpay tax (missing deductions) or underpay (claiming too much), both of which create problems.
Accountants help by making sure you do not miss legitimate expense deductions that many people overlook. They understand how capital allowances work on equipment and vehicles and can advise whether the cash basis or traditional accounting method is more suitable for your situation.
They also help with timing income and expenses in a tax-efficient way and have knowledge of industry-specific reliefs and allowances that could reduce your overall tax bill.
2. Your Income is Over £100,000
Once you exceed £100,000, your Personal Allowance starts disappearing and you lose £1 of allowance for every £2 earned above £100,000. This creates an effective 60% tax rate between £100,000 and £125,140.
Accountants help by planning strategic pension contributions that can help reclaim your Personal Allowance. They understand how the timing of income and bonuses can make a big difference to your tax position and how Gift Aid donations can reduce your adjusted net income.
They also know how to optimise childcare costs and salary sacrifice schemes. At this income level, even small mistakes can cost thousands, not hundreds, which is why careful planning matters.
3. You Have Multiple Income Sources
Multiple employments, rental properties, dividends, foreign income, pension income – each adds complexity and potential for errors.
Accountants add value by checking that your tax code is applied correctly, especially when you have more than one source of income. They make sure expenses are claimed in the right place and not missed, while also understanding how different types of income are taxed in different ways.
By planning how and when income is taxed, they can often reduce your total tax bill rather than letting everything fall into the highest rates.
4. You’re a Company Director
Directors face unique complexities around salary, dividends, loans, benefits, and the interaction between personal and company tax.
When you have an expert accountant for Self Assessment, you get the right balance between salary and dividends, which can save thousands each year. They manage director’s loan accounts carefully, as even small mistakes can lead to costly tax charges.
They also ensure benefits in kind are reported correctly and coordinate Corporation Tax with personal tax so everything works together efficiently rather than creating unnecessary liabilities.
5. You Have Rental Property
Property income involves allowable expenses, mortgage interest restrictions, capital allowances, and potential Capital Gains Tax on disposal.
Accountants support landlords by correctly working through the reduced mortgage interest relief, which is no longer a simple deduction and often catches people out. They identify expenses that are easy to overlook, such as travel costs, insurance, and maintenance work.
They also handle the complexities around capital allowances for furnished properties and help decide whether the £1,000 property allowance makes more sense than itemising every expense. When a property is sold, they plan ahead for Capital Gains Tax so unnecessary tax is not paid.
6. You Have Capital Gains
Sold shares, a second property, or business assets? Capital Gains Tax is notoriously complex with annual exemptions, different rates for different assets, and reliefs most people don’t know about.
7. You Receive Untaxed Income
Foreign income, trust income, or other untaxed sources require you to calculate and pay the correct tax – get it wrong and you face penalties and interest.
8. You’re Claiming Complex Reliefs
Research and Development (R&D) tax credits, Enterprise Investment Scheme (EIS) relief, Venture Capital Trust (VCT) relief, or other specialist reliefs require expertise to claim correctly.
9. You’ve Made Mistakes Before
If you’ve previously filed incorrect returns, faced penalties, or struggled to understand HMRC correspondence, professional help prevents recurring problems.
10. Your Time is Valuable
Even if you could file yourself, is it the best use of your time? If you bill £50-£100+ per hour in your business, spending 5-10 hours on Self Assessment costs you £250-£1,000 in opportunity cost – potentially more than an accountant’s fee.
Making Your Decision
Ask yourself these questions:
- Is my situation truly simple? (One employment, minimal other income, no complex reliefs needed)
- Am I confident I won’t miss deductions or make errors?
- Do I have time to complete it properly? (Not rushing at the deadline)
- What’s my time worth? (Your hourly rate x hours needed vs. accountant fee)
- Can I afford mistakes? (Penalties, underpayments, overpayments)
- Am I comfortable dealing with HMRC if they query something?
- Do I need strategic tax advice beyond just filing?
If you answered “no” or “unsure” to several of these, an accountant probably makes sense.
Our Recommendation
For most people reading this article, professional help is worthwhile. The tax system is complex, constantly changing, and mistakes are costly. Unless your affairs are genuinely simple (single employment, minimal other income, no business), the value accountants provide – in tax saved, time reclaimed, and stress avoided – almost always exceeds their fees.
We specialise in Self Assessment for individuals with complex tax situations – self-employed, company directors, landlords, and high earners. Our service includes comprehensive tax planning, not just form-filling. Most clients save more in tax than our fees cost, while reclaiming hours of their time.
Book a free consultation to discuss your specific situation. We’ll honestly tell you whether you need our help or can manage yourself – and if you do need us, we’ll explain exactly what we’ll do and what it costs. No surprises, no pressure.
Call 020 4617 7555, email info@fluxaccounting.co.uk, or visit fluxaccounting.co.uk to get started.
