Self Assessment Expenses

Self Assessment Expenses Explained

If you’re unsure what you can and can’t claim on your tax return, this guide to Self Assessment expenses explained will help.

Understanding which costs are allowable could reduce your tax bill significantly.

What Are Self Assessment Expenses?

HMRC allows certain business-related costs to be deducted from your income before calculating tax. These are called Self Assessment expenses, and claiming them correctly means you only pay tax on your profits—not your total income.

Common Allowable Expenses

Here are examples of expenses you can usually claim:

Office costs (e.g. stationery, phone bills)
Travel costs (fuel, train tickets)
Staff costs (wages, subcontractors)
Premises costs (rent, business rates, utilities)
Advertising and marketing
Accounting or legal fees

Always keep receipts and accurate records.

What You Can’t Claim

Some costs aren’t allowable, such as:

Personal expenses (e.g. holidays, clothes)
Fines or penalties
Entertainment or client gifts (in most cases)

Only claim items that are “wholly and exclusively” for your business.

Using Simplified Expenses

If you’re a sole trader or small business, you can use HMRC’s flat rates for:

Vehicle use
Working from home
Living at your business premises

Simplified expenses make it easier to calculate and report costs on your Self Assessment.

Get Help with Your Self Assessment Expenses

With over 30 years of experience, I make sure your Self Assessment expenses are accurate and fully compliant—so you don’t miss out on any tax savings.

Need Help with Self Assessment?

I’ve helped hundreds of people file accurate tax returns on time, save money and avoid penalties.

📞 Call: 07867 410938

📧 Email: ross@moorefinancialmanagement.wales

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