Self-Assessment 2025: What to Do Now to Prepare Early

If tax returns always catch you off guard, you’re not the only one. Many small business owners and freelancers leave self-assessment until the last minute. However, rushing can lead to mistakes, missed deadlines, and unexpected tax bills. This guide will help you get started early in 2025 and avoid the stress later.

Make Sure You’re Set Up with HMRC

If this is your first time filing a self assessment tax return, you’ll need to register for Self Assessment with HMRC before you can submit anything. This tells HMRC you have income that isn’t taxed automatically like from freelancing, self-employment, or rental income.

You must register by 5 October 2025 if you earned money between 6 April 2024 and 5 April 2025 that needs to be declared.

To register:

• Create a Government Gateway account.

• Fill in your details and the reason you're registering (e.g. self-employed).

• HMRC will send you a 10-digit UTR (Unique Taxpayer Reference) by post.

• Once you get it, you can set up your online Self Assessment account and get ready to file.

RECOMMENDED READING: How to Complete a Self Assessment Tax Return?

Even if you’ve done this before, it’s worth logging into your HMRC account early to make sure everything still works. Waiting until January to find out you’ve lost your login, or never registered at all, is a headache you can avoid.

Start Organising Your Records

To get ready for your 2025 tax return, it’s important to start collecting and sorting your financial records now. Don’t wait until January.

Here’s what you’ll need:

• Proof of income – Things like client invoices, bank statements, or records from platforms like Etsy or Upwork.

• Business expenses – Keep receipts for anything related to your work (travel, phone bills, software, materials, etc.). These can lower your tax bill.

• Other income – If you earn from things like property, dividends, or side gigs, make sure you keep records of those too.

You can store this info in a spreadsheet, an app, or accounting software - whatever helps you stay on top of it.

Tip: HMRC recommends keeping these records for at least 5 years after the self assessment tax return deadline, just in case they ever ask to see them.

Estimate and Budget for Your Tax Bill

If you don’t want a surprise tax bill in January, start estimating what you might owe now and set money aside little by little.

Here’s how to make it easier:

• Use HMRC’s online calculator to get a rough idea of your tax bill based on your income.

• A good rule of thumb? Save around 25–30% of everything you earn. This usually covers your tax and National Insurance.

• Set up a separate savings account just for tax - it keeps things clean and avoids dipping into money you’ll need later.

Also, keep in mind if your tax bill is over £1,000, HMRC may ask for payments on account, meaning you pay part of next year’s tax early (in January and July).

RELATED: Why Is My Self Assessment Tax So High?

Staying ahead now helps you avoid stress, interest, and penalties down the line.

RELATED: What Happens If You Don't File Self Assessment in the UK?

What We Think

The Self Assessment system can be hard to navigate, especially for small business owners and freelancers who are expected to get it right without much help. For people already managing everything on their own, it can feel confusing and unfair.

We think HMRC could do more to make the process simpler and clearer, especially for those who are new to self-employment. Until that happens, the best way to stay in control is to start early, stay organised, and ask for support when needed.

How JAFA Can Help

We use AI technology for bookkeeping that keeps your records up to date automatically, so you’re not scrambling to find receipts or add up income at the last minute. You’ll get clear, real-time estimates of what you owe, so you can budget with confidence - no guesswork needed.

And if you're ever unsure about something, we’re here to help. Our team can guide you through the process step by step, so you're not left figuring it out alone.

Contact our expert accountants based in Birmingham, UK, either by booking a FREE discovery call or calling us on +44 121 227 6277.