Separate three different amounts
A selling price can contain VAT, the marketplace can charge VAT on its fees, and your supplier can charge VAT on the product. These amounts have different roles. A single “include VAT” checkbox is often too vague to model them correctly.
VAT inside a customer price
For normal VAT accounting, a £30 price that includes 20% VAT contains £5 of VAT. The price excluding VAT is £30 ÷ 1.2 = £25. Subtracting 20% of £30 would remove £6 and leave the wrong revenue amount.
If the seller is not VAT-registered, the calculators do not deduct output VAT from the sale. Select your actual situation rather than assuming that a standard product rate means every seller must deduct that amount.
VAT on marketplace fees
A £5 VAT-exclusive fee with 20% VAT costs £6 on the invoice. A seller who cannot recover that VAT has a £6 effective cost. If the VAT is fully recoverable under normal VAT accounting, the profit estimate can use the £5 cost and show the £1 recovery separately.
A VAT-inclusive fee needs a different calculation. TikTok’s published standard commission includes applicable taxes, so adding another 20% on top would count fee VAT twice. The TikTok tool extracts the VAT within the commission instead.
Enter effective product and extra costs
Our tools ask for effective product, delivery and extra costs after eligible VAT recovery. If a supplier invoice totals £12 and you can recover its £2 VAT, enter £10. If you cannot recover the VAT, enter £12. This keeps the model simple without assuming that every purchase contains recoverable VAT.
Cases outside the model
The tools cover normal VAT accounting with a selected product rate and optional full platform fee VAT recovery. Flat Rate Scheme, margin schemes, partial recovery, imports and marketplace-deemed-supplier transactions can require different treatment. The calculator is not a VAT return or a replacement for transaction records.
Check your customer price, supplier invoices and marketplace fee invoice separately. Then match the calculator settings to those amounts.
HMRC: charge, reclaim and record VAT · TikTok commission policy. Reviewed 14 October 2026. Your account statement remains the final reference.
Put the numbers to work
Try the Amazon UK FBA, eBay UK business or TikTok Shop UK calculator. Review every fee line and compare more than one selling scenario.