Understanding when to submit a tax return in the UK
Navigating the UK tax system can feel confusing, especially if you are filing for the first time or your circumstances have changed.
For many people, tax is collected automatically through PAYE. However, if you have income that is not fully taxed at source, or if HMRC needs more information about your tax position, you may need to submit a Self Assessment tax return.
This guide explains some of the common situations where a tax return may be required.
Who may need to submit a tax return?
You may need to submit a tax return if one or more of the following apply to you.
You are self-employed
If you are self-employed as a sole trader and earned more than £1,000 before deducting expenses, you will usually need to register for Self Assessment and submit a tax return.
You are a partner in a business partnership
If you are a partner in a business partnership, you will usually need to submit a tax return to report your share of the partnership income.
You receive rental income
If you receive income from renting out property, you may need to declare this to HMRC. This can apply whether you have one rental property or a larger property portfolio.
Landlords should also be aware that Making Tax Digital for Income Tax is being introduced for many individuals with property and/or self-employment income.
You have foreign income
If you receive income from outside the UK, you may need to report it through Self Assessment. This can include overseas rental income, employment income, dividends, pensions, or other investment income.
The UK tax treatment of foreign income can be complex, so it is worth taking advice if you are unsure.
You have untaxed income
You may need to submit a tax return if you receive income that has not been taxed before you receive it.
Examples can include freelance work, consultancy income, tips, commission, investment income, or other income not dealt with through PAYE.
You have made a capital gain
If you sell or dispose of an asset that has increased in value, you may need to report the gain and pay Capital Gains Tax.
This can apply to assets such as shares, second homes, buy-to-let properties, business assets, or other investments.
You or your partner claim Child Benefit
If you or your partner claim Child Benefit and one of you has income above the current High Income Child Benefit Charge threshold, you may need to report this to HMRC.
In some cases, the charge can be collected through PAYE. In other cases, Self Assessment may be required.
Your income is high or your tax position is more complex
If your income is high, your personal allowance is affected, or your income comes from several different sources, you should check whether you need to submit a tax return.
You may also need to file if HMRC asks you to do so.
Registering for Self Assessment
If you need to submit a tax return and have not filed one before, you must register with HMRC.
The usual deadline to tell HMRC is 5 October following the end of the tax year in which the income or tax obligation arose.
Once registered, HMRC will issue you with a Unique Taxpayer Reference, known as a UTR. You will need this to file your tax return.
Tax return deadlines
The UK tax year runs from 6 April to 5 April.
The usual Self Assessment deadlines are:
- 5 October: deadline to register for Self Assessment if you need to file and have not done so before
- 31 October: deadline for paper tax returns
- 31 January: deadline for online tax returns
- 31 January: deadline to pay any tax due for the previous tax year
If payments on account apply, a second payment deadline may also fall on 31 July.
Making Tax Digital for Income Tax
Making Tax Digital for Income Tax is being introduced for many sole traders and landlords.
Under MTD, affected individuals will need to keep digital records and submit quarterly updates to HMRC using compatible software.
The current timetable is:
- From 6 April 2026: individuals with qualifying income over £50,000
- From 6 April 2027: individuals with qualifying income over £30,000
- From 6 April 2028: individuals with qualifying income over £20,000
Qualifying income generally includes income from self-employment and property.
If you are self-employed, a landlord, or both, it is worth checking early whether MTD may apply to you.
First-time filers: what to prepare
If you are filing a tax return for the first time, it helps to gather your records before starting.
Depending on your circumstances, this may include:
- Employment income details
- Self-employment income and expenses
- Rental income and property expenses
- Bank interest
- Dividend income
- Pension income
- Capital gains information
- Foreign income
- Student loan information
- Child Benefit information
- Pension contributions and Gift Aid donations
Keeping organised records throughout the year makes the tax return process much smoother.
Returning filers: when circumstances change
You may have filed tax returns in the past and then stopped because your income became simpler or was taxed through PAYE.
However, you may need to file again if your circumstances change.
Common examples include:
- You start self-employment or freelance work
- You begin receiving rental income
- You sell an asset and make a taxable gain
- You receive foreign income
- You become a partner in a business
- Your income increases and affects your tax position
- HMRC sends you a notice to file
If you receive a notice to file from HMRC, you should not ignore it. Even if you believe no tax is due, you may still need to respond or ask HMRC to withdraw the notice.
When to ask for advice
Tax filing obligations can change from year to year, especially if your income, employment status, property ownership, or family circumstances change.
If you are unsure whether you need to submit a tax return, CooperFaure can help you understand your position and advise on the next steps.
We support individuals, sole traders, landlords, company directors, and business owners with Self Assessment, property income, Capital Gains Tax, and Making Tax Digital preparation.