Self Assessment is a HM Revenue and Customs process for collecting Income Tax. This collection is from people whose income is not taxed through Pay As You Earn. Although many people pay tax on their income through their employment. But others have to calculate their own tax liability by completing a Self Assessment tax return. It is important to understand who needs to do Self Assessment. This helps you to avoid being penalised for failing to complete a tax return.
This guide will tell you:
- Who has to do Self Assessment
- What income needs to be reported
- How to check your obligations
What Is Self Assessment?
Self Assessment is a process that enables a person to calculate how much tax they owe on their income for a tax year. Because in this process tax is not automatically deducted. The person has to calculate how much tax they owe and pay it to HMRC.
The tax year in the UK is from 6 April to 5 April every year. If a person is required to file a Self Assessment tax return, then they have to do so and pay the tax due by the deadlines. This process affects a large number of people. In this process it affects the:
- Self-employed
- Landlords
- Company directors
- People with high incomes
Self Assessment is important because it ensures that people who have untaxed or partially taxed income pay the right amount of tax. This process also enables HMRC to collect National Insurance contributions and capital gains tax.
Who Must File a Self Assessment Tax Return?
You must file a Self Assessment tax return if any of the following apply to you during the tax year:
Self-employed people
If you are self-employed and earn more than one thousand pounds before expenses then you must register and file a tax return and this applies to:
- Freelancers
- Contractors
- People with a side business
Business Partners
If you are a partner in a business partnership, this means you must file a tax return to report your share of the profits.
People with high income
If your total income exceeds one hundred thousand pounds then you must file a tax return so that HMRC can calculate your tax liability.
People with untaxed income
You might need to file a tax return if you have untaxed income. In this it involves:
- Rental income
- Tips
- Commissions
- Savings income
- Dividends
- Casual income
Landlords
If you earn income from renting out property in the UK or abroad. It means you must usually file a tax return.
People with capital gains
If you sell assets and earn profits above the annual exemption then you must report them through Self Assessment.
High Income Child Benefit Charge
If you or your partner earns over fifty thousand pounds and claims Child Benefit, don’t forget to file a tax return to pay the charge.
People asked by HMRC
If HMRC asks you to file a tax return then you must do so. This applies even if you have simple finances.
Who May Also Need to Complete Self Assessment?
Some individuals are not automatically required to submit a tax return. But in many cases it may need to do so depending on their situation.
Company directors are often required to complete a Self Assessment tax return. This is important especially if they receive dividends or other forms of untaxed income. Individuals with multiple sources of income may also need to submit a tax return. In this it involves employment and other sources of income like freelancing or property income,
Individuals claiming specific tax reliefs may find it beneficial to complete a tax return. Individuals who wish to make voluntary National Insurance contributions or prove their self-employment status for benefits or grants may also need to use Self Assessment.
Kinds of Income That Require Self Assessment
Property income
Income from property in the UK or abroad usually needs to be reported. In this it usually includes furnished holiday lettings and long-term rentals. All property income must be reported even if expenses are claimed.
Investment income
If your dividend income exceeds the dividend tax allowance or your savings income exceeds tax-free rates then you may need to file a tax return. This is also important even if tax has already been paid.
Foreign income
Income from abroad may need to be reported to get the right tax treatment which is usually from employment income to pensions or property income along with investments.
Side income or online income
Income may need to be reported if it exceeds certain allowances. It usually comes in online sales, freelancing, blogging or Online platforms. It’s also important to report if you have other side income
How to Check If You Need to File a Tax Return?
HMRC offers an online service. In this service you are allowed to check if you need to file a Self Assessment tax return. It simply asks the answers to a few questions then you will know if you need to file a tax return.
First-time Self Assessment taxpayers must register with HMRC by 5 October after the end of the tax year in which they received taxable income. For instance, if you received taxable income in the tax year ending 5 April 2025, you must register with HMRC by 5 October 2025.
Missing the deadline to register with HMRC may mean that you incur penalties, even if you are late in filing your tax return.
Key Deadlines for Self Assessment
Registration Deadline
If you are required to file a tax return for the first time then you must register by 5 October following the end of the tax year.
Filing Deadlines
Paper tax returns are due by 31 October following the end of the tax year. Online tax returns are due by 31 January. Most people now file online. The reason for this much online filling is that it is more convenient and deadlines are extended.
Payment Deadlines
Tax payments are due by 31 January following the end of the tax year. In some instances, payments in advance may also be due with a second payment due by 31 July.
Missing deadlines results in automatic penalties and interest. As a result it is essential to meet the deadlines. Missing the filing deadline can lead to penalties in which you automatically receive a one hundred pound penalty even if you owe no tax. If you miss then after three months daily penalties of ten pounds per day can apply for up to ninety days.
Conclusion
It is essential to know who has to complete a Self Assessment in order to remain compliant with UK tax legislation, whether you are self-employed or receive rental income. It also includes dividends or high income. It is essential to understand your requirements to avoid unnecessary penalties.
By assessing:
- Your situation early
- Maintaining good records
- Adhering to deadlines
you can handle your tax affairs effectively and efficiently. If you are unsure then it is always best to consult HMRC or a tax professional to remain compliant with your legal obligations.
People Also Ask
Who must file a Self Assessment tax return?
Those who are:
- Self-employed
- Landlords
- Business partners
- High earners
- Those with untaxed income
Do I have to file a tax return if I earn less than one thousand pounds?
Not normally, thanks to the trading allowance. But this is except for other taxable income.
What will happen if I miss the deadline?
Missing deadlines will result in automatic penalties and interest will apply.
Can I file my tax return online?
Most tax returns are filed online through the HMRC website.
How do I register for Self Assessment?
Register online with HMRC to get your Unique Taxpayer Reference number for filing.
When is the deadline for Self Assessment?
The deadline for online filing and payment is 31 January after the end of the tax year.
Do I need an accountant to do my Self Assessment?
No, you can do it yourself online, but an accountant can assist if your tax affairs are complicated.
