End of Tax Year Checklist for Sole Traders
End of Tax Year Checklist for UK Sole Traders: Avoid HMRC Penalties Before 5 April
If you’re a sole trader in the United Kingdom, the weeks leading up to 5 April can feel uncomfortable. You know the tax year is ending, you’ve heard scary stories about HMRC fines, and you might be wondering:
“What if I’ve missed something and get a penalty later?”
You’re not alone in feeling that way. The good news is that you don’t need to have a perfect set of accounts to get started – you just need a simple, practical end of tax year checklist to follow.
In this guide, I’ll walk you through clear, doable steps so you can:
Get your records into shape
Make sure you haven’t missed income or expenses
Understand what happens after 5 April
Reduce the risk of surprise tax bills or penalties from HM Revenue & Customs (HMRC)
What the end of the tax year actually means (and why it matters)
The UK tax year runs from 6 April to 5 April the following year. For example, the current tax year runs from 6 April 2025 to 5 April 2026.
Your end of tax year checklist is all about making sure that everything that happened in your business between those dates is correctly captured:
All income you earned in that period
All allowable business expenses you paid in that period
Any tax payments you’ve already made (for example, payments on account)
You do not submit your Self Assessment tax return by 5 April. Instead:
The paper tax return deadline is usually 31 October after the end of the tax year.
The online Self Assessment deadline (and the deadline to pay the tax) is 31 January after the end of the tax year.
If you miss that filing or payment deadline, HMRC can charge:
An automatic £100 late filing penalty, even if no tax is due
Further penalties if your return or payment is more than 3, 6 or 12 months late
Getting organised before 5 April gives you plenty of time to file early and avoid those charges.
Step 1 on your end of tax year checklist: tidy your records
Before you worry about tax calculations, focus on getting your records complete and tidy. This alone reduces a huge amount of anxiety.
Bring your income up to date
Go through the whole tax year and:
Download bank statements for your business account
Check invoices issued – have you recorded them all, including small or one-off jobs?
Match each payment in your bank to an invoice or clear description
Make a note of any unpaid invoices (you still report the income depending on your accounting method, but it’s useful to see who owes you)
If you’ve been mixing personal and business money in one account, don’t panic. For now, carefully mark which transactions are business-related; then, as part of your end of tax year checklist, plan to open a separate business account for next year to make life easier.
Check your record-keeping meets HMRC expectations
HMRC expects self-employed people to keep adequate business records and to retain them for at least 5 years after the 31 January submission deadline for the relevant tax year.
That means:
Keep copies of invoices and receipts (digital copies are fine)
Keep bank statements and any loan or finance agreements
Store everything somewhere safe and backed up
If you move your records into bookkeeping software or a well-organised spreadsheet now, it will make this tax return – and future ones – much less stressful.
Step 2: capture every allowable expense before 5 April
Next on your end of tax year checklist is making sure you’ve included all the allowable expenses you can claim. Allowable expenses are the day-to-day costs of running your business – things like:
Office costs: stationery, phone bills, software subscriptions
Travel costs: fuel, parking, train or bus fares when travelling for business
Marketing and website costs
Professional fees, such as accounting or legal advice
A fair share of home running costs if you work from home
HMRC’s guidance is clear that you can only claim costs that are wholly and exclusively for your business, or a fair business proportion where something is used personally as well (for example, mobile phone or broadband).
Practical actions now:
Go through your bank statements for the whole tax year and highlight every business cost
Check your email for digital receipts and subscriptions
Gather paper receipts and either scan or photograph them
Note any recurring payments (software, hosting, insurance) and make sure they are included
Many sole traders under-claim because they’re afraid of getting it wrong. If in doubt, make a list of “questionable” items and ask a professional to review them, rather than leaving them out completely.
Step 3: check your tax position and set money aside
Once you’ve pulled together income and expenses, you can estimate your taxable profit (income minus allowable expenses). This is the figure your Income Tax and Class 4 National Insurance are based on.
HMRC sets a tax-free Personal Allowance each year – currently £12,570 – and then charges Income Tax on income above that level in different bands.
At this stage in your end of tax year checklist, aim to:
Roughly estimate your tax bill
Use simple percentages (for many basic-rate sole traders, setting aside around 20–30% of profit is a reasonable starting point, though your exact rate will depend on your total income and circumstances).
HMRC’s online calculators or commercial tools can help you refine this.
Check what you’ve already paid
If you’re in the Self Assessment system already, you may have made payments on account in January and July. These are advance payments towards your next bill.
Start or top up a “tax pot”
Move money regularly into a separate savings account labelled “Tax”.
Treat that money as not yours – it already belongs to HMRC.
By doing these sums soon after 5 April, you avoid the unpleasant surprise of realising in January that you owe far more than you’d expected. You can also choose to file your return early, even though the official deadline is 31 January. Filing early doesn’t make you pay sooner unless you choose to; it just gives you clarity.
Step 4: plan ahead – digital records, MTD and getting support
The final part of your end of tax year checklist is about making next year easier than this one.
Move towards digital record-keeping
HMRC is gradually rolling out Making Tax Digital (MTD) for Income Tax. From April 2026, many self-employed people with higher income will have to keep digital records and send quarterly updates through compatible software, with the thresholds reducing over time.
Even if you’re not caught by MTD immediately, starting to use simple cloud accounting software or a well-structured spreadsheet now will:
Reduce the risk of lost receipts
Make it easier to see what you’re earning and spending in real time
Save you time (and fees) when you or your bookkeeper prepare your tax return
Decide what you’ll handle yourself – and where you want help
You absolutely can learn the basics of Self Assessment, but you don’t have to do everything alone. Many small service business owners prefer to:
Do day-to-day record-keeping themselves (issuing invoices, logging expenses)
Hand over the year-end checks, tax calculations and filing to a bookkeeper or accountant
If you feel nervous, confused, or you’ve started trading mid-year or added a side-hustle, getting professional support for a year or two can give you the confidence that everything is set up correctly and compliant.
You don’t have to fear 5 April
The end of the tax year doesn’t need to be a moment of panic. With a straightforward end of tax year checklist, you can:
Tidy your records and meet HMRC’s expectations
Capture all your allowable expenses
Estimate your tax bill and set money aside
Plan for digital record-keeping and future changes like Making Tax Digital
If you’d like some calm, practical support with your bookkeeping or Self Assessment – or you’d simply like someone to walk through your figures with you – I’d be very happy to help.
You can contact me via my website www.lavenderledger.co.uk to arrange a free, no-pressure discovery call. We’ll talk through where you are, what you’re worried about, and how to make your next tax year feel far more manageable.
