What is a Self Assessment tax return?
Self Assessment is HMRC’s system for collecting Income Tax and Capital Gains Tax from people whose tax isn’t deducted automatically at source. You must register, obtain a Unique Taxpayer Reference (UTR), keep accurate digital records and file the correct return by the deadline. Late filing brings automatic penalties and interest, and inaccurate returns can lead to HMRC enquiries.
Who must file
- Sole traders and partners
- Company directors
- Landlords and property investors
- Contractors operating outside PAYE
- Individuals with foreign income
- Anyone with income over £100,000
- Anyone with untaxed income, such as dividends, savings or capital gains
- Anyone HMRC has issued a notice to file
What feeds into your return
| Income source | What it covers |
|---|---|
| Self-employment | Trading profits from your business |
| Property | Rental income from UK and overseas property |
| Investments | Dividend and savings income |
| Foreign income | Earnings and income from overseas |
| Pensions | Pension income |
| Employment | Employment income not fully taxed at source |
| Capital gains | Gains from disposing of assets |
Legitimate business expenses, Marriage Allowance, pension contributions, Gift Aid and other reliefs must be identified correctly to avoid overpaying.
Our Self Assessment services
Tax return preparation
Complete, HMRC-ready SA100, SA800 and SA900 returns, personal tax computations and SA302 reconciliations.
Income and gains reporting
Self-employment, rental, dividend, foreign and capital gains income, including CGT calculations.
Compliance and filing support
Student loan and Child Benefit charge calculations, online filing, tax planning and quality-assured review.
Client types we support
Construction professionals often need CIS-aware handling. Landlords need specialist rental income and CGT treatment. Contractors and IT consultants may need IR35-aware reporting, and high-net-worth individuals often have income across dividends, foreign earnings and capital gains.
- Professional services
- IT consultants
- Construction
- Healthcare
- Retail
- Hospitality
- Real estate
- Financial services
- Legal firms
- E-commerce
- Contractors
- Limited company directors
FAQs
Frequently asked questions
What is a Self Assessment tax return?
The annual return used to report income and capital gains to HMRC and calculate any tax due where it isn’t collected through PAYE.
What is an SA100?
The main Individual Tax Return form, reporting personal income, gains and reliefs, plus any supplementary pages needed.
Do you prepare SA800 and SA900 returns?
Yes. SA800 partnership returns including partner profit allocations, and SA900 trust and estate returns.
Can you calculate Capital Gains Tax?
Yes, for property, shares and other assets, including reliefs, exemptions and 60-day residential property reporting.
Can you report rental and foreign income?
Yes, including UK and overseas property income, foreign income and double taxation relief.
How secure is my information?
Data is shared through encrypted, access-controlled portals under strict confidentiality agreements and GDPR-aligned handling.
Can you help during the January rush?
Yes. We prepare and file your return accurately and on time, so you avoid last-minute stress and missed deadlines.