Self Assessment Tax Returns for Sole Traders Fixed-Fee London Accountant - MTD Ready

Fixed-fee, HMRC-compliant self assessment tax returns for sole traders and the self-employed. From £350. No surprises. Avoid the January panic.

View Pricing
GET A QUOTE

ICAEW Chartered Accountant Regulated & Qualified

HMRC Registered Agent Authorised to act on your behalf

Sage QuickBooks Xero All major platforms supported

East & South London Offices Local accountant, national reach

In Person & Online Meet us or work remotely

THE SERVICE

Expert sole trader accountant — accurate, on time, and stress-free

As a sole trader, your Self Assessment tax return is one of your most important annual obligations. Get it wrong and HMRC may charge penalties, interest, or request an enquiry. With the right accountant, you may find legitimate savings you didn't know existed.

Circular3 handles Self Assessment returns for sole traders across all industries — from freelancers and consultants to tradespeople and e-commerce sellers. Our chartered accountants ensure your return is filed accurately, on time, and with every allowable business expense claimed. We quote a fixed fee upfront, based on your income and complexity. No hidden charges.

What This Service Does for You

What This Service Enables You to Do

  • Meet your HMRC deadline with confidence

    31 January deadline for online returns — filed on your behalf via HMRC agent credentials

  • Claim every allowable business expense

    From mileage and home office to equipment and professional subscriptions — everything is checked

  • Know your tax bill in advance

    Your liability & payments on account are calculated so you can plan your cash flow — no January shocks

  • Avoid late filing penalties

    There is a £100 automatic penalty for late filing — the deadline is never missed

  • Prepare for Making Tax Digital (MTD)

    MTD ITSA applies from April 2026 for sole traders earning over £50k — get ready now

Who Needs to File a Self Assessment Tax Return

Do I Need to File a Self Assessment as a Sole Trader?

Freelancer, taxi driver, gig worker, tradesperson, consultant, side hustler — it doesn't matter what you call it.

Whether you're a freelance consultant logging hours on a laptop, a craftsperson running a workshop, a self-employed professional managing a full client list, or just running a side hustle — your Self Assessment return has the same hard deadline and the same potential penalties.

Earned over £1,000 self-employed? If you are a UK resident and earned more than £1,000 before expenses during the tax year (6 April to 5 April), you must notify HMRC and file a Self Assessment return — regardless of whether you also have employment income.

Circular3 works with sole traders across every industry and income level. The pricing structure supports people at all income levels and supports you to do as much as you are comfortable with. Your chartered accountant can do more than file — they can check, optimise, and advise.

Freelancers & Consultants Tradespeople & Craftspeople Taxi & Private Hire Drivers Gig Workers & Delivery Riders E-commerce Sellers Creative Professionals Contractors & CIS Workers Side Hustles Healthcare & Therapy Professionals

What's Included

What's Included in Your Sole Trader Self Assessment Tax Return

Everything below is covered in your fixed fee — fully managed by your ICAEW Chartered Accountant.

Your Tax Return, Filed for You

Accurate preparation and direct HMRC submission — with full confirmation once accepted.

  • SA100 & SA103 preparation
  • Tax computation
  • National Insurance (Class 2 & 4)
  • HMRC filing & confirmation
  • Deadline & payment reminders
£

All Income & Reliefs Covered

Every income source declared, every relief claimed — so you never pay more tax than necessary.

  • Bank & savings interest, UK dividends
  • Pension income & higher rate relief
  • Gift Aid & charitable giving
  • Student loan repayment calculation

Advice & Peace of Mind

Your return explained in plain English — and practical guidance to stay on top of things year-round.

  • Clear explanation of what you owe and why
  • Payments on account calculation
  • Digital record keeping guidance
  • MTD readiness advice

All of the above is included in your fixed fee — no surprises. Capital gains, CIS deductions and bank reconciliation are available as optional extras.

Get a Quote
From £375 Fixed fee, no surprises
ICAEW Regulated
MTD Ready 2026
HMRC Agent

Transparent Fixed-Fee Pricing

How Much Does a Sole Trader Self Assessment Cost?

Fees shown are estimates based on your income band, the timetable and the complexity of the work. A fixed fee estimate will be agreed with you before any work begins.

Every return includes:  SA100 & SA103 preparation  ·  Tax computation & NIC (Class 2 & 4)  ·  Bank interest, UK dividends & pension income  ·  HMRC filing & confirmation  ·  Payments on account calculation  ·  Deadline & payment reminders
Record ComplexityWhat this meansTotal Fee
SimpleCloud accounting + bookkeeper/automation + <50 transactions/yr£375£450 incl. VAT
ModerateSpreadsheet records + owner-maintained + 50–250 transactions/yr£450£540 incl. VAT
ComplexRaw data / paper + not maintained + 250–1,000 transactions/yr£575£690 incl. VAT
Highly ComplexFull reconstruction needed + 1,000+ transactions/yr£725£870 incl. VAT
Record ComplexityWhat this meansTotal Fee
SimpleCloud accounting + bookkeeper/automation + <50 transactions/yr£425£510 incl. VAT
ModerateSpreadsheet records + owner-maintained + 50–250 transactions/yr£525£630 incl. VAT
ComplexRaw data / paper + not maintained + 250–1,000 transactions/yr£650£780 incl. VAT
Highly ComplexFull reconstruction needed + 1,000+ transactions/yr£825£990 incl. VAT
Record ComplexityWhat this meansTotal Fee
SimpleCloud accounting + bookkeeper/automation + <50 transactions/yr£500£600 incl. VAT
ModerateSpreadsheet records + owner-maintained + 50–250 transactions/yr£625£750 incl. VAT
ComplexRaw data / paper + not maintained + 250–1,000 transactions/yr£775£930 incl. VAT
Highly ComplexFull reconstruction needed + 1,000+ transactions/yr£950£1,140 incl. VAT
Record ComplexityWhat this meansTotal Fee
SimpleCloud accounting + bookkeeper/automation + <50 transactions/yr£575£690 incl. VAT
ModerateSpreadsheet records + owner-maintained + 50–250 transactions/yr£725£870 incl. VAT
ComplexRaw data / paper + not maintained + 250–1,000 transactions/yr£900£1,080 incl. VAT
Highly ComplexFull reconstruction needed + 1,000+ transactions/yr£1,100£1,320 incl. VAT
Returning Client Discount
10% off
Applied to your total fee before VAT
Multi-Return Discount
5% off
Per additional return filed at the same time (e.g. household)

The fee quoted is an estimate based on the timetable, provision of information and scope of work assumptions. Should these assumptions turn out to be incorrect, Circular3 reserves the right to notify you of a revised figure or range and seek your agreement to the change, before continuing. VAT charged at 20%. Fees shown are for sole trader Self Assessment — additional income sources such as property, capital gains or foreign income are quoted separately.

Optional Add-Ons

Additional Services — Quoted Separately

The following are not included in the standard fee and are only added if needed, based on your individual circumstances. Each is quoted and agreed before any work begins.

Reconciliation

Bank & income reconciliation Reconcile bank statements and income sources to records
£85 per source
VAT reconciliation Reconcile VAT returns to accounts
£55 per trade

Self-Employment

Capital allowances (AIA / WDA) Annual Investment Allowance and writing down allowance calculations
£85 per trade
Private use adjustments Motor, home office and mixed-use asset apportionment
£60 per asset
CIS deductions Construction Industry Scheme subcontractor tax deductions
£65 per trade
Stock / work-in-progress Year-end stock valuations and WIP adjustments
£50 per trade

Capital Gains Tax

CGT — simple disposal Listed shares, unit trusts
£75 per disposal
CGT — complex disposal Property, business assets, PRR, letting relief, BADR
from £150 per disposal

Other Add-Ons

Rental property income UK residential property income included on your return
£50 per property
Marriage allowance transfer Transfer of personal allowance between spouses
£20 fixed
EIS / SEIS / VCT relief Investment scheme tax relief claims
£50 fixed
HMRC 64-8 agent registration New client authorisation setup — one-off
£50 one-off

Turnaround Time

Standard (4+ weeks) Normal processing time
No surcharge included
Priority (2–4 weeks) Faster turnaround
+£75 adjustment
Urgent (<2 weeks) Rush processing — deadline or late filing
+£175 adjustment

All add-on fees are estimates and will be confirmed before work begins. Add-ons are only included if required — you will not be charged for anything not agreed in advance. All fees exclude VAT at 20%.

⚠️ Upcoming Change

Making Tax Digital for Sole Traders — Are You Ready for April 2026?

From April 2026, sole traders earning over £50,000 must comply with Making Tax Digital for Income Tax (MTD ITSA) — meaning quarterly digital submissions to HMRC, replacing the single annual return. The £30,000 threshold follows in April 2027.

April 2026 MTD mandatory >£50k
April 2027 MTD mandatory >£30k
April 2028 MTD mandatory >£20k
Get MTD Ready — Book a Call

Common Questions

Sole Trader Self Assessment — Frequently Asked Questions

Answers to the questions sole traders ask most about Self Assessment, deadlines, expenses and Making Tax Digital.

How much does a Self Assessment tax return cost for a sole trader?
Fee estimates at Circular3 start from £375 for a simple return (income up to £50k, cloud accounting, bookkeeper-maintained, low transaction volume). Fees rise based on your income band and record complexity. All fees are estimates agreed in writing before any work begins. Our fees are transparently priced and competitive for London.
What is the Self Assessment deadline for sole traders?
The online Self Assessment deadline is 31 January following the end of the tax year (5 April). For the 2024/25 tax year, the deadline is 31 January 2026. A £100 automatic penalty applies if you miss it — rising significantly after 3 and 6 months. Filing well before Christmas is recommended to allow time to plan your tax payment.
Do I need to register for Self Assessment as a sole trader?
Yes — if you earn more than £1,000 from self-employment in a tax year, you must register for Self Assessment and file a return. You must register by 5 October following the tax year you started trading. For example, if you started in June 2025, register by 5 October 2025. Circular3 can assist with HMRC registration and your first return.
What expenses can I claim as a sole trader?
Allowable expenses include office costs, travel and mileage, stock and materials, marketing, professional subscriptions, bank charges, accountancy fees, training, and a proportion of home costs if you work from home. You can also claim capital allowances on equipment (Annual Investment Allowance up to £1 million). Every return includes an expenses review to ensure nothing is missed.
What happens if I file my Self Assessment late?
HMRC imposes an automatic £100 penalty for returns filed 1 day late — regardless of whether you owe any tax. After 3 months, daily £10 penalties apply (up to £900). After 6 months, a further penalty of 5% of the tax due (or £300, whichever is greater) is charged. Returns are always filed well ahead of the deadline.
Does Making Tax Digital affect my sole trader Self Assessment?
Yes, if your income exceeds the relevant threshold. From April 2026, sole traders earning over £50,000 must submit quarterly digital updates to HMRC via MTD-compatible software, replacing the single annual return. The £30,000 threshold follows in April 2027. A full MTD onboarding service is available — software selection, setup, and ongoing quarterly compliance.
Does using Xero or QuickBooks reduce my accountancy fee?
Yes — using cloud accounting software is the single biggest driver of the Simple complexity tier, which attracts the lowest fee. Clean, well-maintained digital records allow your return to be prepared efficiently. If you're still on spreadsheets or paper records, the fee will reflect the additional work involved.
Can you handle CIS subcontractor Self Assessment returns?
Yes. Construction Industry Scheme (CIS) returns for subcontractors are handled as an add-on to the standard sole trader return at £65 per trade, including reclaiming CIS tax deducted by contractors and reconciling deductions against amounts paid.