Do I Need to Complete a Self Assessment Tax Return?

Not everyone needs to complete a Self Assessment tax return.

For many people, Income Tax is dealt with automatically through PAYE. However, if you are self-employed, receive rental income or have other income or gains that have not been dealt with through PAYE, you may need to tell HMRC and complete a tax return.

The rules depend on the type and amount of income you receive, so it is important not to assume that having tax deducted from your main job means you cannot also need a tax return.

Who normally needs to complete a Self Assessment tax return?

There are a number of circumstances that can create a Self Assessment requirement.

Common examples include:

• You were self-employed as a sole trader and had gross trading income of more than £1,000
• You were a partner in a business partnership
• You had to pay Capital Gains Tax when you sold or disposed of something that increased in value
• You had to pay the High Income Child Benefit Charge and it is not being collected through PAYE
• You have untaxed income that needs to be reported, such as certain property income, savings interest, dividends or foreign income
• HMRC has issued you with a notice requiring you to submit a tax return

This is not an exhaustive list. Whether a return is required can depend on your individual circumstances and HMRC provides an online checker if you are unsure.

I’m employed. Can I still need a tax return?

Yes.

Being employed and paying tax through PAYE does not prevent you from also needing Self Assessment.

For example, someone could have a full-time job while also receiving income from:

• A side business
• Freelance work
• Rental property
• Savings or investments
• Dividends
• Foreign sources

Whether this results in a Self Assessment requirement depends on the nature and amount of the additional income and your circumstances.

I started a side business. Do I need to register?

If your gross trading income from self-employment is more than £1,000 for the tax year, you will normally need to consider registering for Self Assessment as a sole trader.

The £1,000 figure relates to income before expenses, not profit.

Where gross trading income is £1,000 or less, the trading allowance can mean that you do not need to tell HMRC in some circumstances. There are exceptions, however, and there can also be situations where someone chooses to report the income.

Important

The £1,000 trading allowance relates to gross trading income, not taxable profit. For example, receiving £1,500 from a side business and having £800 of expenses does not mean your income is below the £1,000 threshold.

Do landlords need to complete a tax return?

Receiving rental income can create a requirement to report property income to HMRC.

However, whether you need to complete a Self Assessment tax return depends on the amount and circumstances, including the level of property income, allowable expenses and whether the property allowance or another relief applies.

Check your individual position if you are unsure whether a return is required. For more on rental expenses, read What Expenses Can Landlords Claim Against Rental Income?.

Do company directors automatically need a tax return?

No.

Being a company director, by itself, does not automatically mean that you need to complete a Self Assessment tax return.

However, a director may still need to complete one because of their individual circumstances. For example, they may have income or gains that need to be reported through Self Assessment.

What if HMRC has asked me to complete a tax return?

If HMRC has issued you with a notice requiring you to complete a tax return, you should not simply ignore it because you believe you no longer meet the normal Self Assessment criteria.

Important

If HMRC has asked you to submit a tax return, you should submit the required return by the relevant deadline or contact HMRC to have the filing requirement withdrawn where appropriate. Simply deciding that you no longer need to file can result in unnecessary penalties.

When do I need to register for Self Assessment?

For someone who needs to report income for the 2025/26 tax year, the normal deadline to tell HMRC is 5 October 2026 where they:

• Have not sent a tax return before, or
• Were previously registered but did not need to send a tax return for 2024/25

Depending on the circumstances, someone who has previously been within Self Assessment may need to reactivate their Self Assessment account rather than register from scratch.

Deadline

If you need to complete a tax return for 2025/26 and need to register or reactivate Self Assessment, the normal notification deadline is 5 October 2026.

What are the Self Assessment deadlines?

For the 2025/26 tax year, the main deadlines are:

If you register after 5 October 2026, HMRC may provide a different filing deadline. However, this does not automatically change the normal 31 January 2027 payment deadline for tax due for 2025/26.

There is also an earlier filing deadline if you want HMRC to consider collecting an eligible Self Assessment liability through your PAYE tax code.

What is a UTR?

A UTR is your Unique Taxpayer Reference.

When you register for Self Assessment for the first time, HMRC provides you with a UTR. It is used to identify your Self Assessment tax record and is required when dealing with HMRC about your return.

If you ask an accountant to prepare your tax return but have not yet registered for Self Assessment, the registration process may therefore need to be completed before the return can be submitted.

When do I have to pay the tax?

For the 2025/26 tax year, the normal deadline for paying the Self Assessment balancing payment is 31 January 2027.

However, some taxpayers also have to make payments on account towards the following year’s liability.

This can make the first January payment considerably larger than someone expects if they have not budgeted for it.

What are payments on account?

Payments on account are advance payments towards the following year’s Income Tax and, where relevant, Class 4 National Insurance.

There are normally two instalments:

• 31 January
• 31 July

Each payment on account is normally half of the relevant previous year’s liability.

Payments on account are generally not required where the relevant amount is less than £1,000 or where more than 80% of the tax due was collected outside Self Assessment.

Example

If your Self Assessment liability used to calculate payments on account was £3,000, you could potentially need to pay £4,500 on 31 January: the £3,000 balancing payment plus a £1,500 first payment on account towards the following year.

A further £1,500 payment on account would then normally be due on 31 July.

The exact calculation depends on the amounts included in the Self Assessment liability, so the figures should be checked rather than assuming that every tax bill automatically creates payments on account.

Can payments on account be reduced?

Yes.

If you reasonably expect the following year’s relevant tax liability to be lower, you can apply to reduce your payments on account.

For example, this might be relevant where profits have fallen or a source of income has stopped.

Important

Payments on account should not be reduced simply to delay paying tax. If they are reduced too far and the eventual liability is higher, HMRC can charge interest on the shortfall.

What records do I need for my tax return?

The records required depend on the income and circumstances being reported.

They might include:

• Employment documents such as P60s and P45s
• Self-employment income and expenses
• Bank interest
• Dividend information
• Rental income and expenses
• Pension income
• Investment reports
• Details of asset disposals relevant to Capital Gains Tax
• Foreign income information
• Relevant pension contributions
• Gift Aid donations

You should keep sufficient records to support the figures included on your tax return.

Should I wait until January to do my tax return?

No.

You can submit a Self Assessment tax return after the end of the relevant tax year. You do not need to wait until January.

Filing earlier does not normally mean that the tax itself has to be paid immediately.

Completing the return earlier can mean that you:

• Know what you owe sooner
• Have more time to budget
• Can identify missing information earlier
• Avoid the pressure of approaching the filing deadline

For a 2025/26 return, the tax year ended on 5 April 2026, so the return can be prepared well before the 31 January 2027 online filing deadline.

What about Making Tax Digital for Income Tax?

Some sole traders and landlords are now within Making Tax Digital for Income Tax from 6 April 2026.

MTD introduces digital record-keeping and quarterly reporting requirements for people who fall within the rules.

For a fuller explanation, read Making Tax Digital for Income Tax: What Sole Traders and Landlords Need to Know.

How can Baldwin’s Accountancy Services help?

We can help determine whether you need to complete a Self Assessment tax return, register with HMRC where necessary and prepare and submit the return on your behalf.

We can also calculate your tax liability, explain any payments on account and let you know what needs to be paid and when.

If you have several sources of income, such as employment, self-employment, rental income, dividends or investments, we can bring the relevant information together as part of the return.