What are the UK tax return deadlines in 2023?

Small BusinessCategory
6 min read
Sage Becker

US statesman Benjamin Franklin once said that nothing in the world is certain except for death and taxes.

You’ll have to submit a Self Assessment Tax Return every year without fail if you: 

  • Are self employed 
  • Rent out property
  • Are a partner in a business
  • Have any other form of untaxed income 
Overhead view of a beauty salon owner at a laptop

If you have set up a business as a Limited Company, you will need to file a Company Tax Return every year. This could be instead of — or as well as — a Self Assessment Tax Return, depending on how you have structured your company’s finances.  

With the first of this tax year’s deadlines approaching, it’s time to make sure you have all the tax return dates clearly marked up in your diary. If you miss them, you could incur penalties.  

In this article, we highlight the timelines for submitting your tax returns and answer a few questions that new business owners and start-ups commonly have about tax.

What is a tax return? 

A tax return is a document that is used to work out how much tax a business or person owes HM Revenue and Customs (HMRC) every tax year, which runs from April to April. 

For many people in the UK, the tax they owe is deducted automatically by PAYE, every week or month when they are paid their salary, along with National Insurance. 

However, around 12 million people in the UK do not pay their taxes in this way. 

These people have to file a tax return through a system called Self Assessment, before a cut-off date set by HMRC every year.  

As mentioned above, owners of Limited Companies have to file Company Tax Returns. Again, these could be instead of or on top of a Self-Assessment Tax Return.  

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Who needs to do a tax return? 

If you earn any income outside of PAYE, you’ll usually need to file an income tax return. 

This includes: 

  • Sole traders
  • Partners in businesses 
  • Anyone who earns previously untaxed money from renting out property 
  • Those who earn extra income from savings, investments and dividends 
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If you have set up in business as a Limited Company as opposed to a Sole Trader, you’ll be liable for Corporation Tax every year and have to file a Company Tax Return.  

Still not sure if you need to file a tax return? Visit this page. 

Related: 25 side hustle ideas to make extra money this year

How do I complete a tax return? 

The system used for filing and paying an income tax return is called Self Assessment.


When it comes to filing it, you can do so online or by filling in a paper SA100 form.  

The Self Assessment form features a series of questions relating to your: 

  • Income 
  • Expenses  
  • Student loan payments, if you have any of these outstanding 

Once you have filled out the questions, the Self Assessment system will generate a figure for the amount of tax you owe.  

Is it easy to do your own tax return? 

Woman looking at receipts on desk with pink calculator nearby

Filing out a tax return for the first time usually takes some time and effort.

It will be easiest to carry out your Self Assessment if you have kept your accounts up to date throughout the year, detailing all income and outgoings.  

Some people like to use accounting software like GoSimpleTax or an accountant to help them get their figures right. This also helps ensure they are including all the correct expenses on their reports.  

Pro tip: Open a separate bank account for your small business. Your tax returns will be much easier to complete if your business income and expenses have been kept separate from your personal finances. 

When does the tax year run from and to? 

The tax year (aka the fiscal year) runs from 6th April to 5th April the following year.

What are the tax return deadlines for 2023? 

5th October 2023: If you intend to file a tax return for the first time, you must inform HMRC of this intention by October 5th 

31st October 2023, midnight: This is the deadline for submitting your 2022/2023 Self Assessment by paper.  

31st January 2024, midnight: This is the deadline for submitting your 2022/2023 online Self Assessment Tax Return and for paying the tax you owe. 

31st July: Once you have paid your first tax bill, HMRC usually begins to take payments in advance of the money you will earn the following year. The deadline for making these advance payments is July 31st, 2024.   

Deadline for submitting a Company Tax Return: This is due 12 months after the end of the accounting period it covers. This is usually the same period as the financial year but may be different in your first year of business.  

Deadline for paying Corporation Tax: Nine months and one day after the end of the accounting period.

What expenses can I claim for on my tax return? 

Claiming for expenses is a complicated subject, which is why both sole traders and company directors regularly enlist accountants to help them get everything right.  

Different rules apply, depending on whether you are a sole trader or Limited Company.  

For sole traders, some expenses related to the running costs of your business can be deducted from your taxes owed to work out your taxable profit.

Worker wearing a brightly coloured uniform

For example… 

Let’s say your turnover is £40,000, and you claim £10,000 in allowable expenses. You only pay tax on the remaining £30,000, known as your taxable profit. 

You can only deduct ‘allowable expenses’ though. 

These could include: 

  • Office costs such as stationary, postage, ink cartridges, insurance costs etc 
  • Car, van and travel expenses including hotel rooms and train fares etc 
  • Clothing expenses like uniforms and protective clothing 
  • Staff expenses such as pensions 
  • Legal and financial costs including overdraft and banking charges 
  • Marketing, entertainment and subscriptions: This is where you usually claim for the cost of your website, web hosting and professional email address. 

There are specific rules about how to claim for expenses in each of these categories. (You'll find a complete list here.)

To find out more about the difference between Sole Trader and Limited Company expenses and to dig deeper into the specifics of what each expense category includes, visit this site.

This post does not represent tax advice. It's best to consult with a tax professional when preparing your tax returns.

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