October 5th Self Assessment Deadline What You Need to Know

Miss the 5 October registration deadline and January can get stressful fast. If you’ve started freelancing, gone self-employed, rented out a property, or earned money outside your normal job, this is the date to have on your radar.

The short version is this: 5 October is the deadline to register for a tax return if you need to send one for the first time. It applies after the end of the tax year in which you started earning that income.

So if you started working for yourself during the tax year that ended on 5 April, you usually need to register by 5 October that same year.

This guide is general information, not personal tax advice. If your situation is messy, it’s worth speaking to an us at Keeping it Balanced.

A simple reminder can save a lot of January panic.

What the 5 October deadline actually means

The UK tax year runs from 6 April to 5 April.

If you earn money that isn’t already fully taxed, you may need to tell HM Revenue and Customs. The deadline to do that is 5 October after the tax year ends.

Here’s a simple example.

You started freelance work in July 2025. That falls in the tax year ending 5 April 2026. If you need to send a tax return for that year, you should register by 5 October 2026.

Registering doesn’t mean you pay your tax that day. It means you’re telling the tax office that you need to complete a return.

The main later date to know is 31 January, which is usually when online tax returns and payments are due.

Who needs to register by 5 October

You may need to register if you’ve started earning income outside a normal job. This often includes:

• Working for yourself as a freelancer

• Starting a small side business

• Becoming self-employed

• Earning money from renting out property

• Getting untaxed income from tips, commissions, or casual work

• Being a partner in a business partnership

• Earning taxable income from abroad

• Earning money from Vinted and Ebay or other selling sites

  
  

For many freelancers, the key point is whether your self-employed income is more than the small trading allowance. If you earn more than that amount before taking off costs, you’ll usually need to register.

A common search is “Sole trader, property, when do i need to register”, and the simple answer is this: if your untaxed income started in a tax year that has just ended, check whether you need to register by the following 5 October.

Property income can be a bit different depending on how much rent you receive, what costs you have, and whether you own the property with someone else. Don’t ignore it just because you also have a regular job.

Freelance income is easier to handle when the paperwork isn’t left until the last minute.

What happens if you miss the deadline

Try not to panic if 5 October has already passed. Missing the registration deadline doesn’t always mean an instant fine by itself.

The bigger risk is that registering late can delay the details you need to file your return. If that delay causes you to miss the January filing deadline or pay late, penalties and interest can follow.

That’s why it’s best to register as soon as you realise you need to.

Late registration can also make everything feel more rushed. You may need time to:

• Find income records

• Add up expenses

• Check bank statements

• Understand what counts as business spending

• Set money aside for the tax bill

  
  

January is much easier when you’re not trying to do all of that for the first time.

How to register if you’re newly self-employed

If you’re registering for the first time, you’ll usually do it online through the government website.

Check how to register for Self Assessment - GOV.UK

The exact route depends on whether you’re self-employed, registering because of property income, or registering for another reason.

You’ll generally need a few details to hand:

• Your name and address

• Your National Insurance number, if you have one

• The date you started working for yourself

• A short description of what you do

• Basic contact details

  
  

After you register, you’ll receive details that let you manage your tax account and file your return online. These can take a little while to arrive, so don’t leave it until the last few days if you can help it.

For Self assessment, the goal isn’t to make things perfect on day one. The goal is to get set up properly so you can report your income and pay the right amount on time.

A simple list of income and costs is a good place to start.

What to do before you register

Before you start, take 20 minutes to pull together the basics. It’ll make the form less annoying.

Work out when you started

Use the date you first began earning from the activity, not the date you opened a bank account or made a logo.

For example, if you sent your first paid invoice in May, that’s likely the date that matters.

Check whether your income counts

Look at your total income before expenses. If you sold services, did freelance projects, rented out a room or property, or did regular paid work outside employment, don’t assume it’s too small to matter.

Small one-off amounts may not lead to a tax return, but regular income often needs checking.

Keep your records simple

You don’t need fancy software from the start. A clear spreadsheet or notebook can work for a new freelancer if it includes:

• The date money came in

• Who paid you

• What the payment was for

• Any costs linked to the work

• Receipts or proof of payment

  
  

Good records mean fewer guesses later.

Common mistakes to avoid

The biggest mistake is waiting until January to think about it. By then, you may be trying to register, gather records, file the return, and pay the bill all at once.

Another mistake is assuming a side income doesn’t count because tax has already been taken from your main job. Your wages and your freelance or rental income are looked at together when your tax is worked out.

Also, don’t mix up registering with filing. Registering by 5 October is only the first step. Filing the return and paying what you owe usually come later.

FAQ

Do I need to register if I only earned a small amount?

Maybe not, but check carefully. Some small amounts are covered by allowances. If your income goes over those limits, you may need to register.

Is 5 October the payment deadline?

No. It’s the registration deadline. The main online filing and payment deadline is usually 31 January after the tax year ends.

What if I have a job and freelance on the side?

You may still need to register. Tax from your job doesn’t automatically cover income from freelance work.

Do I need an accountant?

Not always. Many people with simple income do it themselves. If you have property income, several income sources, or you’re unsure what expenses count, help can be useful.

What should I do if I missed 5 October?

Register as soon as you can. The sooner you start, the more time you’ll have to file correctly and avoid late filing or payment problems.

Keeping the key dates visible makes the whole process feel less vague.

The simple next step

If you started earning untaxed income in the last tax year, don’t wait for January to figure it out. Check whether you need to register, gather your basic details, and get it done before 5 October if the deadline applies.

A little admin now can save a lot of stress later.