The Self Assessment Deadline Is Looming

If the words “Self Assessment” trigger a mild sense of panic, you’re not alone. Every January, thousands of people promise themselves they’ll “do it earlier next year”… and then find themselves staring at the self assessment deadline wondering where the time went.

So, with 31 January 2026 approaching for the 2024–25 tax year, now is a very good moment to get clear on what’s required, who needs to submit a return, and what actually needs pulling together.

No scare tactics. No jargon. Just the facts and how we can help make it all a lot less painful.

Who needs to complete a Self Assessment tax return?

Self Assessment isn’t just for “business owners” in the traditional sense. You’ll usually need to file a return if you’re:

• A sole trader

• A landlord with rental income

• Earning money from a side hustle (Etsy, Vinted, freelance work, online selling, etc.)

• Receiving untaxed income that HMRC doesn’t already know about

Even if it’s not your main source of income, HMRC still expects to be told about it. If you’ve earned money outside PAYE, it’s worth assuming Self Assessment applies and checking properly rather than hoping for the best.

Key dates for the 2024–25 self assessment deadline

Let’s get the important bit out of the way:

• 31 January 2026 is the deadline to:

  • File your online Self Assessment tax return

  • Pay any tax owed

  • Pay your first payment on account (if applicable)

Miss this date, and penalties start automatically. HMRC doesn’t wait for excuses.

What information do you need to complete your return?

You don’t need to memorise everything, but having the right information ready makes the whole process far less stressful.

Income

Depending on your situation, this could include:

• Self-employed income

• Rental income

• Side hustle or freelance earnings

• CIS income

• Dividends

• Interest

• Any other untaxed income

Expenses

For sole traders and landlords, allowable expenses might include:

• Office costs

• Travel

• Utilities

• Insurance

• Repairs and maintenance

• Software and subscriptions

• Professional fees

(Claiming what you’re entitled to matters. It can make a big difference to the final bill.)

Other information

You may also need:

• Your Unique Taxpayer Reference (UTR)

• Records of previous payments on account

• Details of Student Loan repayments

• Child Benefit information (if applicable)

Good records make this smoother. Scrabbling through emails and bank statements in January… less so.

What are payments on account?

This one catches a lot of people out.

If your tax bill is over £1,000, HMRC usually asks for payments on account. These are advance payments towards next year’s tax.

That means in January you may need to pay:

• The balance of tax for 2024–25

• Plus the first payment on account for 2025–26

It’s not extra tax, just paid earlier. However, it can feel like a nasty surprise if you’re not expecting it.

What happens if you miss the deadline?

HMRC penalties are surprisingly efficient.

• £100 automatic fine for filing late (even if you owe no tax)

• Daily penalties if delays continue

• Interest charged on unpaid tax

• Additional penalties for longer delays

In short: ignoring it doesn’t make it go away. It just makes it more expensive.

Why leaving it late is rarely a good idea

January Self Assessment often comes with:

• Rushed decisions

• Missed expenses

• Stress

• Unnecessary penalties

• Very little sleep

Starting earlier gives you:

• Time to check the numbers

• Time to plan for the payment

• Time to ask questions

• Time to breathe

Future you will absolutely appreciate it.

How we can help

If Self Assessment is sitting on your to-do list gathering dust, this is where we step in.

We can:

• Confirm whether you need to file

• Tell you exactly what information is required

• Prepare and submit your tax return accurately

• Explain the figures in plain English

• Help you plan for the payment

• Make sure everything is done properly and on time

Most importantly, we take the pressure off so you’re not trying to decode tax rules late at night with a calculator and a strong coffee.

Final thoughts

Self Assessment doesn’t have to be stressful but it does need attention. If you’re a sole trader, landlord, or earning income on the side, the 31 January 2026 deadline matters. Getting organised now gives you options, clarity, and far fewer headaches.

If that deadline has been quietly hovering in the background, consider this your friendly nudge.

A little action now can save a lot of stress later and we’re here to help every step of the way.