Self Assessment · SA100 · MTD ITSA

Self Assessment Tax Returns

Accurate, timely Self Assessment tax returns for sole traders, freelancers, landlords, and individuals with complex income. We manage your entire return — from gathering records to HMRC submission — and ensure every allowable deduction is claimed.

Who We Help

Sole traders and self-employed
Freelancers and contractors
Landlords with rental income
Company directors
High earners (income over £100,000)
Individuals with investment income
Partners in business partnerships
Employees with multiple income sources

Key Deadlines — 2025/26 Tax Year

5 April 2026End of 2025/26 tax year
5 October 2026Register for Self Assessment if new to filing
31 October 2026Paper return deadline
31 January 2027Online return deadline and balancing payment
31 July 2027First payment on account for 2026/27
Frequently Asked Questions

Who needs to complete a Self Assessment tax return?

You must complete a Self Assessment tax return if you: are self-employed or a sole trader; have income over £100,000 from employment; have untaxed income from rental properties; have foreign income; have income from investments, dividends, or savings above the tax-free allowances; are a partner in a business partnership; or are a company director. You may also need to file if you received COVID support payments that need to be reported.

What is the Self Assessment filing deadline?

The online Self Assessment deadline is 31 January following the end of the tax year. Paper returns must be filed by 31 October. Tax owed (balancing payment) is also due 31 January. A payment on account (an advance payment towards next year's tax) is due 31 July. HMRC charges automatic penalties for late filing starting at £100.

What expenses can I claim as a sole trader?

Allowable expenses for sole traders include: cost of goods sold; business premises costs (rent, utilities, insurance); staff costs; travel costs (fuel, vehicle hire, public transport) for business journeys only; marketing, advertising, and website costs; professional subscriptions and training directly related to your trade; accountancy fees; and a proportion of home office costs if you work from home. Personal expenses are not deductible.

How does Making Tax Digital affect Self Assessment?

From April 2026, sole traders and landlords with gross income above £50,000 must use MTD-compatible software and submit quarterly updates to HMRC instead of an annual return. The annual Self Assessment return is replaced by a Final Declaration. ScaleUp Accounting Ltd manages this process for affected clients.

Can you reduce my Self Assessment tax bill?

Within the bounds of the law, yes. We review your income sources, allowable expenses, capital allowances, pension contributions, and available reliefs to ensure you pay no more tax than is legally required. Common missed allowances include the trading allowance, marriage allowance, and home office relief.

File your Self Assessment stress-free

Contact us to get started. We will send you a simple checklist of the information we need and take care of everything from there — including the HMRC submission.

Book a Free Consultation