Tax Return Self Assessment: A Step-by-Step Guide for Beginners

Filing a Tax Return Self Assessment for the first time can feel overwhelming. From registering with HMRC to calculating your income and expenses, there’s a lot to consider. But with the right guidance and support, the process becomes much more manageable.

At Stewart Accounting, we specialise in helping individuals and small business owners complete their Tax Return Self Assessment accurately and on time. In this guide, we’ll break down everything you need to know — step by step.

Whether you’re a freelancer, sole trader, landlord, or earning income outside your regular employment, this comprehensive guide is tailored to help you understand the entire process.

What Is a Tax Return Self Assessment?

A Tax Return Self Assessment is a system used by HMRC (HM Revenue and Customs) to collect income tax from individuals and businesses that do not have tax automatically deducted from their income. This includes:

Self-employed individuals
Company directors
Property owners earning rental income
Individuals with high investment income
Those with foreign income

If you fall into any of these categories, it’s your responsibility to report your income and pay any tax due through the Tax Return Self Assessment system.

Who Needs to File a Tax Return Self Assessment?

You are required to submit a Tax Return Self Assessment if any of the following apply:

You’re self-employed and earned more than £1,000
You’re a partner in a business partnership
You earned income from renting out a property
You received dividends or other investment income
Your income was over £100,000
You earned income from overseas sources
You claimed Child Benefit but your income was over £50,000

Even if you’ve paid tax through PAYE, if you have additional income, you must complete a Tax Return Self Assessment to report it.

Step-by-Step Guide to Filing Your Tax Return Self Assessment

Step 1: Register with HMRC

Before you can file a Tax Return Self Assessment, you need to register with HMRC:

Self-employed individuals must register by 5th October after the end of the tax year in which they started trading.
You can register online through HMRC’s official portal.
After registration, HMRC will send you your Unique Taxpayer Reference (UTR), which you’ll need to file your return.

Step 2: Gather Your Financial Records

Organised records make the Tax Return Self Assessment process much easier. You should collect:

Bank statements
Invoices and receipts
P60s, P45s, and P11Ds
Details of any income from savings, investments, or property
Details of allowable business expenses

Step 3: Choose the Right Filing Method

You can file your Tax Return Self Assessment either online or by paper form:

Online filing is quicker, offers instant confirmation, and gives you more time — the deadline is 31st January.
Paper filing must be completed by 31st October.

Most people prefer the online method due to its convenience and speed.

Step 4: Fill in the Tax Return Form

When completing your Tax Return Self Assessment, make sure to:

Enter your income from all sources
Deduct allowable expenses (for example, office supplies, travel, etc.)
Include any tax reliefs or allowances (like pension contributions or charitable donations)

Step 5: Submit Your Return and Pay Any Tax Owed

Once you’ve reviewed all the information, submit your Tax Return Self Assessment and pay any tax due by 31st January. You may also need to make Payments on Account, which are advance payments towards your next tax bill.

If you owe more than £1,000 in tax, HMRC may ask you to pay in two instalments — one on 31st January and another on 31st July.

Common Mistakes to Avoid

Filing a Tax Return Self Assessment can lead to penalties if mistakes are made. Here are common errors to watch out for:

Missing the deadline
Failing to report all sources of income
Incorrectly claiming expenses
Not keeping adequate records
Forgetting to make payments on account

Avoiding these mistakes not only saves you money but also ensures compliance with HMRC regulations.

Tips to Make the Process Easier

Start Early – Don’t wait until the last minute to gather documents or complete your return.
Use Accounting Software – This simplifies record-keeping and helps with accuracy.
Stay Organised Year-Round – Keep all receipts, invoices, and bank records sorted monthly.
Hire a Professional – At Stewart Accounting, we offer expert services to guide you through every step of your Tax Return Self Assessment.

How Stewart Accounting Can Help

We understand that dealing with HMRC and tax forms can be stressful — especially if it’s your first time filing a Tax Return Self Assessment. That’s where we come in.

Stewart Accounting offers:

Personalised advice tailored to your income and circumstances
Full preparation and submission of your Tax Return Self Assessment
Assistance with HMRC registration and communication
Identification of allowable expenses to reduce your tax bill
Peace of mind knowing your return is accurate and filed on time

Whether you need a one-time return or year-round tax planning, we’re here to help you stay compliant and confident in your finances.

Deadlines to Remember

Action	Deadline
Register with HMRC	5th October
Submit paper return	31st October
Submit online return	31st January
Pay any tax owed	31st January
Second payment on account (if due)	31st July

Missing these deadlines can lead to penalties and interest, so mark them in your calendar.

Conclusion

Filing your Tax Return Self Assessment doesn’t have to be daunting. With careful preparation, timely action, and support from professionals like Stewart Accounting, you can navigate the process with ease.

Remember, staying compliant is not just about avoiding penalties — it’s also about understanding your financial position and planning for a better future.

If you’re unsure where to start or need expert assistance, contact Stewart Accounting today. We’re here to make your Tax Return Self Assessment journey smooth, simple, and stress-free.

Ready to file your Tax Return Self Assessment? Let Stewart Accounting take care of the details — so you can focus on what matters most.