The Benefits of Submitting Self Assessment Sooner Rather than Later

Remember how you’d always leave homework until the night before it was due, even though your parents and teachers specifically told you not to do this? Do you also remember how much stress it caused you?

Well, you’re a grown up now (hopefully), which means you should know better.

Beyond saving your blood pressure, submitting your Self Assessment tax return well before the deadline actually comes with a whole host of benefits. Which we’ll explain.

Why submit a tax return early?

First and foremost, getting your Self Assessment tax return in sooner gives you more time to plan ahead and get everything ready. This includes making sure you have enough put aside to pay your bill!

It also means you can double-check you have all the (accurate) records you need, such as invoices and bank statements, and those all-important expense claims.

Submitting earlier doesn’t mean you’ll need to pay before the deadline, but you will be able to request any refunds sooner.

Give yourself more time to deal with HMRC

It should also be noted that HMRC’s call centres tend to get overwhelmed in January (meaning delays are likely). You don’t want to sit on hold for seven eternities, give up, and then still land a £100 fine if you miss the 31st January deadline.

The process of submitting your Self Assessment can take quite a while if you’ve never done it before or if you have lots to include. Speaking of which, if this is all brand new to you, make sure you’ve registered first!

Registering for Self Assessment

You can sign up for Self Assessment online. It’s not an instant process. Brace yourself.

You’ll need to set up a GOV.UK login, wait to receive a Unique Taxpayer Reference number – and that’s just the start!

HMRC will then send you a PIN in the post, which you need in order to access online services and actually fill out your tax return.

All this is to say that even if you leave a seemingly reasonable amount of time, you may still find yourself in trouble through no fault of your own. Getting your tax return in as early as possible is undoubtedly the way to go, helping you to avoid the wrath of HMRC (and those pesky fines).

When’s the earliest I can submit a Self Assessment tax return?

You can usually submit a Self Assessment tax return once the year it relates to has ended. The 2024/25 tax year ran from 6th April 2024 to 5th April 2025, meaning the absolute earliest someone could submit a tax return for that year was 6th April 2025. The deadline to submit an online tax return for that year is 31st January 2026.

How do I submit a Self Assessment?

You first need to register for Self Assessment with HMRC by 5th October in the second tax year of your business.

To complete your tax return, you will then need to provide details of any income from that tax year. This includes self-employed income, income from employed work, and that which comes from other sources (dividends, for example).

The deadline for submitting your Self Assessment by post is 31st October, while you have until 31st January to submit it online if you would prefer.

And again, don’t forget your expenses

Bear in mind that if you’re sending a return which includes self-employed income, it’s usually a good idea to also include the details of any expenses relating to it. This is because self-employed people only pay tax on profit, and so expenses get knocked off your income.

A qualified accountant can walk you through the whole process and ensure you don’t get anything wrong.

Alternatively, if you insist on submitting your return yourself, then at least consider using bookkeeping software (Pandle says hello) to manage your transactions. This will help you stay up to date and significantly reduce the chances of inaccurate or incomplete information being included in your Self Assessment by mistake.

Are the submission date and payment date the same?

The deadlines are the same, but you’ll be relieved to learn that submitting a tax return before the deadline doesn’t mean a payment is due straight away.

Even if you submit yours way in advance, you’ll still have until 31st January to pay.

The deadline to submit and pay a tax return for the 2024/25 tax year is midnight on 31st January 2026.

Learn more about using Pandle to make business accounting easier. Create an account today and decide what to do with all the extra time you get back.