Unsold Stock at the End of the Tax Year: Does It Affect Your Online Seller Tax Bill?

If you buy stock to resell and the tax year ends on 5 April with items still sitting in your spare room, you might wonder whether those unsold items affect your tax calculation. The answer depends entirely on which accounting method you are using, and since April 2024, most sole traders are on the simpler method by default, which means the closing stock adjustment that accountants have been explaining for decades does not apply to them at all.

This post covers both scenarios: what happens to unsold stock if you are using the cash basis, which is now the default for most online sellers, and what happens if you have elected to use traditional accruals accounting instead.

The Cash Basis: The Default for Most Online Sellers

Since April 2024, HMRC's default method for sole traders is the cash basis. Under this method, you record income when money arrives in your account and expenses when you pay for them. You do not need to calculate debtors and creditors at year end, perform a stock-take, or estimate accruals and prepayments.

For online sellers, this means stock is expensed when you buy it, regardless of whether you have sold it before 5 April. If you spent £400 on stock in March and only sold half of it before the tax year ended, the full £400 is still deductible in the year you paid for it. The unsold items carry no special tax adjustment into the following year.

This simplicity is the whole point of the cash basis. It aligns your tax records with your actual bank account, removes the need for a year-end stock valuation, and reduces the administrative burden for small sellers who are not running a complex inventory operation.

The majority of online sellers on Vinted, eBay and Etsy are on the cash basis by default unless they have actively opted out. If you have not taken any specific action on this, cash basis is almost certainly your current method.

What Cash Basis Means in Practice for Stock

Under cash basis, the question of unsold stock at year end is straightforward: it has no special tax treatment. You bought it, you deducted the cost, and that is the end of it for this tax year. When the item eventually sells, the proceeds are recorded as income in whichever year the money arrives.

There is one practical consideration worth being aware of. In years where you buy a significant amount of stock that does not sell before 5 April, the cash basis can produce a lower profit figure than accruals would, because you are deducting costs before the corresponding income has arrived. This is generally favourable in terms of cash flow and tax timing, but it means your profit and loss for the year may look worse than your actual trading performance. This is a known characteristic of the cash basis rather than an error, but it is worth understanding if you are using your accounts to assess business health rather than just calculate tax.

When the Closing Stock Adjustment Does Apply

If you have actively elected to use traditional accruals accounting, the picture is different and the closing stock calculation matters. Under accruals, you only deduct the cost of stock you actually sold in the tax year. Unsold stock at year end is treated as an asset that carries forward, and its cost is only deductible when it eventually sells.

The correct way of computing trading profits for tax purposes under accruals is to bring in opening stock and closing stock into the computation at the lower of cost or net realisable value. This rule has been established in case law since 1925 and remains the basis for stock valuation under traditional accounting.

The calculation works as follows:

In this example, only £1,030 of stock cost is deductible this year. The £320 of closing stock carries forward and will be deductible when those items sell in a future year.

A Worked Example: Emma Under Each Method

Emma sells vintage clothing on eBay. During 2026/27 she had £150 of opening stock, bought £1,200 of new stock during the year, and has £320 of unsold stock at 5 April 2027. Her gross income for the year was £2,100.

Under cash basis (default):
Gross income: £2,100
Stock purchased: £1,200 (fully deductible when paid)
Other expenses (packaging, mileage): £205
Taxable profit: £695

Under accruals (opt-in):
Gross income: £2,100
Cost of goods sold: £1,030 (opening stock plus purchases minus closing stock)
Other expenses (packaging, mileage): £205
Taxable profit: £865

Emma pays less tax under the cash basis this year because she can deduct the full cost of stock purchased regardless of whether it has sold. Under accruals, £320 of stock cost is deferred to the following year, producing a higher profit and a higher tax bill now.

Next year, if the £320 of unsold stock sells, the accruals method will produce a lower profit in that year as the deferred cost is recognised. Over time the total tax paid under both methods converges. The difference is timing.

Which Method Is Right for You

For most online sellers, the cash basis is the right default and the simpler option. You expense stock when you buy it, there is no year-end stock-take, and your tax records align naturally with your bank account. HMRC designed the cash basis precisely for this kind of straightforward trading activity.

Accruals accounting may be worth considering if your stock levels are large and growing year on year, because the closing stock adjustment gives a more accurate picture of business performance that a bank or investor would recognise. It may also be worth considering if you are buying significant amounts of stock in one tax year that you expect to sell across several years, because the accruals method matches costs to the income they generate more accurately over time.

If you are unsure which method you are currently on, check your most recent Self Assessment return. The self-employment pages include a box that indicates whether you have elected to use traditional accounting. If that box is not ticked, you are on the cash basis.

Can You Switch Between the Two Methods?

Yes, in principle. You can switch from cash basis to accruals, or from accruals to cash basis, by making an election on your Self Assessment return for the year you want the new method to apply. The switch always takes effect from the start of a new tax year, not mid-year, so if you decide in December that you want to change method, that change will not apply until the following 6 April at the earliest. But possible and straightforward are not the same thing, and for most online sellers the decision to switch deserves more thought than a ticked box.

What Records to Keep Either Way

Under cash basis, keep a record of what you paid for stock, when you paid for it, and what you sold it for when the sale happens. The purchase record is your deduction. The sale record is your income.

Under accruals, you also need to know the value of stock you hold at both the start and end of the tax year. A simple count of unsold items and what you paid for them, noted at 5 April each year, is sufficient for most online sellers. The UK Online Seller Tax Template tracks purchases and sales so your cost of goods sold figure is always available whether you are on cash basis or accruals.

Our post on why your bank balance is not your profit covers the broader principle of matching costs to income, and our guide to whether your selling counts as trading helps you work out whether any of this applies to your activity in the first place.

Get the UK Online Seller Tax Template, £14.99 per year →