Whatnot Seller Tax Guide: What You Need to Know in the UK

Selling on Whatnot can be incredibly rewarding, whether you are selling collectibles, trading cards, sneakers, vintage clothing, beauty products, comics or toys. But once you are trading for profit, HMRC expects the income to be declared.

This guide walks through the UK tax basics for Whatnot sellers in 2026: what income to declare, what expenses you can claim, when to register for Self Assessment, when VAT becomes relevant, and how to stay organised.

Do Whatnot Sellers Pay Tax in the UK?

Yes. If you are trading on Whatnot in the UK, your profit is taxable. It does not matter whether Whatnot is your full-time job or a side hustle. If you are buying stock to resell, running regular shows and making money, HMRC is likely to see this as a trade.

The £1,000 trading allowance

If your total trading income is £1,000 or less in a tax year, you may be covered by the trading allowance. That can mean no Self Assessment registration is needed for that income.

But the limit is based on income before expenses, not profit. It also covers all trading income together, not just Whatnot. If you sell on Whatnot, eBay, Vinted and at local markets, all of that trading income is considered together.

What Income Do You Need to Declare?

In short: all business income connected to your Whatnot selling activity. That includes platform income and any related income earned outside the app.

• Live show sales and auctions.
• Fixed-price sales.
• Private sales connected to your Whatnot business.
• Affiliate commissions.
• Seller bonuses, cashback or incentive payments.
• Tips, gifts or other payments received through the business.
• Sales on other platforms such as eBay, Etsy, Amazon, Vinted, Shopify or your own website.

You declare the income, then deduct allowable business expenses to work out your taxable profit.

How Is Whatnot Income Taxed?

For most new sellers, Whatnot income is treated as self-employment income. You pay tax on profit, which means income minus allowable expenses.

Income Tax

The standard Personal Allowance for 2026/27 is £12,570. For England, Wales and Northern Ireland, Income Tax is charged at 20%, 40% and 45% depending on your total taxable income. Scotland has different Income Tax bands.

You can check current rates on GOV.UK's Income Tax rates page.

National Insurance

Self-employed sellers may also pay National Insurance. For 2026/27, Class 4 National Insurance is charged at 6% on profits between £12,570 and £50,270, then 2% above that. Class 2 is generally treated as paid for eligible self-employed people with profits above the small profits threshold, with voluntary Class 2 still relevant for some low-profit sellers.

See HMRC's self-employed National Insurance guidance for the current position.

Simple example

If you make £30,000 profit from Whatnot and have no other income, your rough tax position could look like this:

• Income Tax: £30,000 minus £12,570 Personal Allowance = £17,430 taxed at 20%, giving £3,486.
• Class 4 National Insurance: £17,430 taxed at 6%, giving £1,045.80.
• Estimated total before any payments on account or adjustments: £4,531.80.

This is only a simplified example. Your actual bill depends on other income, expenses, student loans, pension contributions, payments on account and where in the UK you live.

What Expenses Can Whatnot Sellers Claim?

HMRC allows you to deduct business expenses that are wholly and exclusively for your trade. For Whatnot sellers, expenses usually fall into a few key areas.

Cost of goods sold

The cost of stock you buy to resell is often the biggest deduction. Keep records of what you bought, who you bought it from, when you bought it and how much it cost. This matters even more if you sell second-hand goods, collectibles or mixed lots.

Home office and studio costs

If you run shows, pack orders or manage admin from home, you may be able to claim a portion of household costs. HMRC's simplified working from home rates currently range from £10 to £26 per month depending on hours worked from home, or you can calculate a reasonable business proportion of actual costs.

HMRC explains the flat rates on its working from home simplified expenses page.

Mileage and travel

If you drive to source stock, collect inventory, drop off parcels, attend events or meet suppliers, you may be able to claim business mileage. Simplified mileage rates are 45p per mile for the first 10,000 business miles in a car or van, then 25p per mile after that.

Keep a mileage log showing the date, destination, miles and business purpose.

What you cannot claim

• Personal clothing, unless it is branded workwear or genuinely costume-only.
• Non-business meals and entertainment.
• Fines and penalties.
• Personal purchases described as business research.
• Stock or equipment used personally without adjusting the claim.

HMRC's general guidance on self-employed expenses is a useful reference point.

When Do You Need to File a Tax Return?

Once you need to file Self Assessment, the main deadlines are:

• 5 April: tax year ends.
• 5 October: deadline to register for Self Assessment if you need to file for the previous tax year.
• 31 October: paper tax return deadline.
• 31 January: online tax return deadline and payment deadline.

HMRC has current deadline guidance on its Self Assessment deadlines page.

Payments on Account

If your Self Assessment bill is more than £1,000, HMRC may ask you to make payments on account towards the next year's bill. These are normally due in two instalments: 31 January and 31 July.

This can surprise new sellers because the first January payment may include your tax bill for the year just ended plus the first payment towards the next year. HMRC explains this on its payments on account guidance.

Do Whatnot Sellers Need to Register for VAT?

You must register for VAT if taxable turnover is more than £90,000 in any rolling 12-month period, or if you expect to exceed the threshold in the next 30 days alone.

This includes taxable sales across your business, not just Whatnot. Sales from eBay, Amazon, Etsy, Vinted, Shopify, in-person events and your own website may all count.

VAT is especially important for resellers because you may be dealing with private sellers, VAT-registered suppliers, second-hand goods, margin schemes and platform fees. Do not assume the Flat Rate Scheme is automatically best. Read our Whatnot seller VAT guide before registering.

Should You Set Up a Limited Company?

Most Whatnot sellers start as sole traders because it is simple and cheap to run. A limited company can become worth considering when profits are higher, you want a more formal business structure, or you plan to leave money inside the business.

Corporation Tax is currently 19% for companies with profits of £50,000 or less, 25% for profits over £250,000, with marginal relief between those levels. You can check the current rates on GOV.UK's Corporation Tax rates page.

A limited company is not automatically better. It brings Companies House filings, Corporation Tax returns, payroll, dividends, director responsibilities and more bookkeeping. Get advice before switching.

How to Stay HMRC-Compliant

Keep good records

Track income, platform reports, stock purchases, postage, packaging, mileage, software, storage costs and business bank transactions. If HMRC asks, you need to show where your numbers came from.

Separate personal and business money

A separate business bank account is not legally required for sole traders, but it makes bookkeeping much cleaner. It also helps with VAT, mortgage applications and understanding profit.

Set money aside for tax

A sensible starting point is saving 25% to 30% of profit for tax. If you are a higher-rate taxpayer or have payments on account, you may need to save more.

Use bookkeeping software

Once you have regular sales, use Xero, QuickBooks or similar software. For Simplr clients, Xero and Hubdoc are usually the preferred setup because they keep receipts, bank feeds and reports tidy.

Common Mistakes Whatnot Sellers Make

• Thinking tax only applies once money is withdrawn from Whatnot.
• Using profit instead of income when checking the £1,000 trading allowance.
• Not keeping stock purchase records.
• Mixing personal and business spending.
• Forgetting postage, packaging and platform fees.
• Ignoring VAT until the threshold has already been crossed.
• Not budgeting for payments on account.
• Leaving the tax return until January.

Key Takeaways

• Declare all Whatnot trading income, including live sales, private sales, commissions and bonuses.
• Register for Self Assessment once total trading income is over £1,000 in a tax year.
• Claim allowable expenses such as stock, fees, postage, packaging, mileage, storage and software.
• File your online Self Assessment return and pay tax by 31 January.
• Plan for payments on account if your tax bill is over £1,000.
• Monitor VAT once turnover starts moving towards £90,000.
• Keep business and personal money separate to make records much easier.

Need Help With Your Whatnot Taxes?

At Simplr Accounting, we specialise in helping UK Whatnot sellers stay HMRC-compliant without the stress. From Self Assessment to VAT, bookkeeping to tax planning, we keep the numbers tidy so you can focus on selling.

Book a free discovery call and let’s make your tax simple.