Why Your Bank Balance Is Not Your Profit and Why That Matters for Tax

If you track your online selling income by looking at your bank balance or your total receipts, you are almost certainly looking at the wrong number for tax purposes. The figure your tax is calculated on is different from the amount in your account, different from what the platform paid you, and different from what the buyer actually paid. Understanding this difference is not just a technical accounting point. It is the difference between knowing your real tax position and getting it significantly wrong.

This post explains the chain from gross sale to bank account, what HMRC actually cares about, and why the gap between the two catches more UK online sellers out than almost anything else.

The Chain From Gross Sale to Your Bank Balance

When a sale completes on an online platform, there is a sequence of figures, each smaller than the last.

The buyer pays the full transaction amount. This is the item price plus any delivery charge and any fees the platform charges the buyer directly. This total is your gross income for tax purposes.

The platform then takes its fees. On eBay, the Final Value Fee is deducted before the payment is released to you. On Etsy, the transaction fee and payment processing fee are deducted. On Vinted, the structure works differently because the buyer pays the protection fee separately and you receive the item price in full, which we cover in detail in our Vinted tax guide.

After fees, the remaining amount sits in your platform balance. When you withdraw it, it arrives in your bank account, often as a single consolidated payment covering several days or weeks of sales, with no breakdown of which sale contributed what.

What you see in your bank is the net receipts after all platform deductions, sometimes covering dozens of individual sales in one transfer. It is a useful cashflow figure. It is not your gross income.

What HMRC Calculates Tax On: Gross Sales, Not Your Bank Receipts

For the £1,000 trading allowance threshold and for calculating your taxable profit, HMRC works from gross income, not net income, not bank receipts. Gross income, which is what your buyers paid before the platform took anything.

The reason this matters for the threshold is direct and has real consequences. If your gross income is above £1,000 you need to register for Self Assessment, even if your net receipts after fees dropped below £1,000.

This is what is commonly called the gross income trap. It is not deliberate tax avoidance by the sellers who fall into it. It is simply tracking the wrong number and arriving at the wrong conclusion. The most common cause is checking the bank statement or the platform's payment summary rather than the order-level gross figures.

A Three-Platform Worked Example

The table below shows how gross income, bank receipts and profit differ for a seller trading across three platforms in the same tax year. All three platforms contribute to the single £1,000 trading allowance threshold.

Three things stand out from this table.

The gross income of £1,240 is above the £1,000 threshold. The bank receipts of £1,110 are also above it in this case, but the point is that the gross figure is the one that matters and it is always higher than the bank receipts. For sellers closer to the threshold, the difference between gross and net can be the difference between being above and below it.

The net profit of £580 is significantly lower than both the gross income and the bank receipts, because it accounts for all the seller's costs including fees, delivery and cost of goods. This is the figure the seller actually keeps.

And Vinted shows zero platform fees because Vinted charges the buyer rather than the seller on standard sales. This means the Vinted gross and bank figures are the same. The gross income trap on Vinted comes from buyer-paid delivery rather than fees, which is covered in detail in our guide to tax on PayPal, Vinted and Etsy income.

If you are trading across multiple platforms alongside your day job, our post on how your employment income affects your side hustle tax bill explains how PAYE interacts with online selling income when calculating what you owe.

The UK Online Seller Tax Template handles all of this automatically. You enter the item price, the fees and the buyer-paid delivery separately for each sale, and the template calculates the gross income, tracks it against the £1,000 threshold in real time, and shows your tax position as you go.

Get the UK Online Seller Tax Template, £14.99 →

The Most Common Gross Income Mistake UK Online Sellers Make

Most sellers who get this wrong are not careless. They are doing exactly what seems logical, which is checking what they received and comparing it to the threshold. The problem is that what they received is always lower than gross income, sometimes by a little and sometimes by a meaningful amount.

The gap depends on the platform. On eBay, where Final Value Fees run at around 12 to 14 percent of the total, a seller receiving £880 in bank deposits may have had gross income of around £1,000 to £1,020 before fees. On Etsy, where transaction and payment processing fees combined run at around 9 to 11 percent, the gap is smaller but still material at higher volumes.

The fix is simple in principle, though slightly more work in practice. For each platform you sell on, find the order-level gross figures rather than the payment summaries. eBay shows gross order values in the transaction report. Etsy shows them in the order receipts. Vinted shows item prices in the sales history. Add these up for the tax year (6 April to 5 April) rather than using the calendar year totals the platforms show in their HMRC reporting summaries, which cover January to December and are a different period entirely.

For sellers who want to stay on top of this without manual spreadsheet work, our guide to saving for your sole trader tax bill covers the monthly system that keeps your tax position current throughout the year, not just at January when it is too late to fix problems.

If You Have Already Got This Wrong

If you have been tracking bank receipts and concluding you are below the threshold when your gross income may have been above it, the position is recoverable. The key is to act before HMRC contacts you rather than after.

HMRC now receives sales data directly from Vinted, eBay, Etsy and other platforms through the digital platform reporting rules. The data submitted in January 2026 covers the 2025 calendar year. If your gross income crossed £1,000 in the 2024/25 or 2025/26 tax year and was not declared, the sensible step is to work out what you owed, register for Self Assessment, and file the returns. Coming forward voluntarily before receiving a nudge letter results in significantly lower penalties than being contacted first.

Our post on what happens if you have not registered as self-employed explains the failure-to-notify rules, the penalty calculation, and the steps to put things right. For the broader picture of how the platform reporting rules work and what HMRC receives, our post on how HMRC knows about your side hustle income covers the full picture.

The System That Gets the Right Number Every Time

The UK Online Seller Tax Template is built around this exact problem. You enter the item price, the platform fees and the buyer-paid delivery separately for each sale, and the template calculates the gross sale automatically. The Dashboard tab tracks your gross trading income against the £1,000 threshold in real time and flags when you are approaching or crossing it. You always know your true gross income, not just your bank receipts, and the threshold warning tells you exactly when registration becomes necessary.

Get the UK Online Seller Tax Template, £14.99 →