You may not think this happens, but someone I spoke to lost their house because they didn’t understand how their business structure impacts their taxes. I don’t want this to be you.
In this guide, I’ll give you absolute clarity on how your eCommerce business structure impacts taxes, how it works, who it applies to, and the deadlines you need to know. Get this right, and you can focus on growing your business without tax surprises derailing you.
Sole Trader vs. Limited Company: What’s the Difference?
The structure of your business determines your tax obligations and, more importantly, the level of financial protection you have. Most people do not think about this when they are starting a business because they cannot imaging it going wrong. And it can.
Limited Liability vs. Unlimited Liability
Sole Trader – You and your business are the same legal entity. You are personally liable for all debts.
Limited Company – Your business is a separate legal entity to you. You have limited liability, meaning your personal assets are protected if the business fails.
What Taxes Apply to Each?
Sole Trader – Pays tax through Self-Assessment and pay income tax.
Limited Company – Pays Corporation Tax on profits and dividends on shareholder.
Corporation Tax for Limited Companies
If you run a Limited Company, you pay Corporation Tax on profits.
How Much Corporation Tax Do You Pay?
19% if your profit is below £50,000.
25% if your profit is above £250,000.
If your profit is between these figures, you pay a stepped rate.
For Example: If your profit is £150,000, you pay 24%.
When Do You Pay Corporation Tax?
Accounts must be filed with Companies House within 9 months.
Your tax return deadline is 12 months after your company’s year-end, but this is misleading because you must pay your Corporation Tax within 9 months and 1 day.
Therefore you need to assume your deadline to submit your corporation tax and limited company accounts within 9 months
Example Deadline using companies house data:
You can see here that they incorporated on 28th February 2024:
Their tax year end is 28th February 2025
Accounts and tax return due 9 months after the year end : 30th November 2025.
Corporation tax payment due 9 months and 1 day: 1st December 2025.
You have 21 months before you need to actually file anything if you have just created your company. Just focus on sales!
What you need to do
Miss the deadline? You get fined. Put these dates in your calendar as soon as you create your company. Then, don’t stress about them daily—just ensure your accounts are worked on 3 months before the deadline so you can focus on growing your business.
Self-Assessment for Sole Traders
If you’re a sole trader, you file your taxes through Self-Assessment.
Key Deadlines & Rules
The tax year runs from 6th April to 5th April.
You must file and pay your taxes by 31st January.
You need to register for Self-Assessment by 5th October to get a Unique Taxpayer Reference (UTR).
Example Deadline:
Lets use the same dates as the example above, you start trading in February 2024, your first tax return covers 6th April 2023 – 5th April 2024 and is due 31st January 2025. This will cover 28th February 2024 to 5th April 2024.
What Else to Know?
You’re taxed on top of any other income – this could push you into a higher tax bracket.
Losses can be offset against other income – Sideways Tax Relief – for example, if you made a £10,000 loss in your eCommerce business but earned £60,000 from a job, you can reduce your taxable income to £50,000 and get a £4,000 tax refund. This cannot be done if you are a limited company, only if you are a sole trader.
VAT: When Should You Register?
I am not going to go into the ins and outs of VAT here, we have an article where you can find out more. All you need to know is when to worry about this.
VAT Threshold & Rules
You don’t need to register for VAT immediately. If you do then its generally a costly mistake.
You must register once your UK sales hit £90,000.
Overseas sales do not count, for example FBA sales in the US don’t count towards this threshold—only UK-dispatched sales do.
How VAT Affects Your Business
VAT reduces your margins by around 10%, so pricing must account for this from day one.
Our Rule: Pretend You Are VAT Registered
Not literally—don’t charge VAT if you’re not registered.
But price your products as if you were VAT registered.
This way, your margins hold up after VAT registration.
We have an in depth article and video going into this – so if you want to know how to do it check it out.
Biggest VAT Mistake: Registering Too Early
Don’t rush to register—use the VAT threshold as an advantage.
Only register when necessary, and monitor your UK sales so you know when to act.
Getting It Wrong: Real-Life Disaster Story
So now you understand what ecommerce business structures are available and the key differences. Lets go through a real life example of when it goes wrong.
True Story: A Sole Trader’s £100k VAT Bill
I speak with 100s of businesses and some of these you really remember for the wrong reasons.
James(not his real name) had always dreamed of running his own business. After years of working for someone else, he finally took the plunge and set up an eCommerce store as a sole trader. Sales were slow at first, but a few years, things started to take off. He was making a good profit and reinvesting everything back into the stock so he can grow.
But James made a crucial mistake—he didn’t keep track of his VAT threshold. Without realising it, he crossed the £90,000 VAT threshold. HMRC have all the marketplace data so HMRC eventually caught up with him and sent a letter informing him the needed to back date a VAT registration. We calculated it for him and he owed £100k . Now over a 3 year period, this is not a huge number.
He had no idea VAT had been accumulating in the background. Worse still, he hadn’t set aside any money for it, he invested it all back into stock. Desperate, he looked for a way out. If he had set up as a Limited Company, he could have shut the business down, and his personal assets would have been safe. But as a sole trader, he was personally liable for every penny.
James tried negotiating, but HMRC didn’t budge. He was on a payment plan. His business was now no longer generating the income it once was. and couldn’t keep up with it. He had no choice—he had to sell his house to cover the debt. Years of hard work, late nights, and sacrifices, and now he had lost everything, all because he didn’t understand how his business structure affected his tax obligations.
This didn’t need to happen. Here’s how to avoid this nightmare:
Here are some simple rules every business owner should follow:
If you’re under the VAT threshold, being a sole trader is fine – just plan for self assessment tax payments and file by 31st January.
Don’t register for VAT too early – it eats into your margin even if you are tempted by the reclaim at the start.
If you’re about to exceed the VAT threshold, consider forming a Limited Company – this protects your personal assets from business debts. VAT is another bill every three months which can spiral into a debt.
A sole trader who can’t pay VAT may have their assets seized – a Limited Company can fail without affecting your personal finances.
Check your Companies House records – find your tax return date by adding 9 months to your incorporation date.
Put all deadlines in your calendar – then forget about it and focus on growing your business.
We made a separate guide on how to scale profitably beyond the VAT threshold—check it out and learn how you can make sure your product is profitable from day one.
