Selling price calculator: work backwards from the margin you want
Most sellers pick a price and hope. The stronger move is to fix the margin you need and solve for the price — which takes a solver, because fees and VAT scale with the very price you're choosing.
Published 29 July 2026 · Rates last checked 18 August 2026 · Worked examples computed by the live calculation engine
The problem
"Cost plus 30%" feels safe but answers the wrong question — it marks up the product cost and ignores that eBay's percentage, the regulatory fee and output VAT all grow as the price grows. Price a little higher and your costs quietly grew too. That's why a target price needs solving, not adding.
A worked example
An item costing £11.50 with £3.35 postage and £0.40 packaging, sold on eBay UK by a VAT-registered business seller aiming for a 20% margin:
- Break-even price
- £17.93
- Price for 20% margin
- £23.19
- At £19.99 you'd make
- £1.51
- …which is a margin of
- 9.1%
Anything below £17.93 loses money on this item. The listed price of £19.99 clears the 20% target with a 9.1% true margin; the engine also reports the maximum you could pay a supplier (£7.77 ex VAT) and still hit target at this price.
What the solver does
find price P such that:
profit(P) = revenueExVat(P) − costs − fees(P) = target% × revenueExVat(P)
break-even = the P where profit(P) = 0Assumptions
- eBay UK default category, per-order and regulatory fees included; VAT-registered seller, domestic sale.
- Free postage to the buyer (postage cost is the seller's), packaging included in the solve.
- Margin is measured ex-VAT, matching your accounts.
Frequently asked
- Why can't I just add my costs and my margin on top?
- Because the biggest costs scale with the price you haven't picked yet. Marketplace fees and VAT are percentages of the selling price, so raising the price raises them too. The right price comes from solving that loop, not from a one-way sum.
- What is a break-even price?
- The selling price at which true profit is exactly zero — every fee, VAT effect and cost covered, nothing left. It's your absolute floor for sales, offers and Best Offer auto-accept limits.
- Should I price at the target-margin price?
- It's a starting point, not an order. The market may pay more (take it) or less (now you know exactly what margin you're accepting — or that you should walk away from the product).
- Does the target price account for postage and packaging?
- Yes — everything you enter is in the solve: product cost, courier, packaging, labour, returns reserve, category fees and your VAT position.
Every rate used on this page is public: see the Rate Centre for the exact cards and verification dates, and how we keep the numbers honest.
Run your own numbers
Free, no account needed — the same engine as every example above.
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