MurmMargin — Landed cost & break-even

See what a supplier listing really costs to sell: landed cost, margin, and the ad spend you can afford.

See the real landed cost, profit margin and break-even ad spend on any AliExpress or Alibaba listing. Click the icon on a supplier page and type your sell price. MurmMargin reads the prices the listing declares, builds the cost the way customs actually charges it — goods, freight, duty, VAT, payment fees — and gives dropshipping and ecommerce sellers the number no supplier page shows: how much you can pay for ads per sale before the unit loses money. What you get, on the page you are already on: Landed cost per unit, at your order quantity Profit margin and markup multiple at your sell price Break-even ad spend per sale A live waterfall of where the customer's money goes An alert when the supplier changes the price between visits Duty bands by category and destination, with both edges shown What does this product actually cost to sell? Your customer's money, drawn left to right: goods, freight, duty, VAT, payment fees — each eating its share — ending in the one bright bar that is yours to keep. Change the quantity, the destination or the sell price and every bar, figure and sentence recomputes as you type. A product priced underwater gets no margin bar at all; it gets the shortfall printed as a number, because a chart should not soften bad news. Arithmetic that refuses to flatter you Duty is charged on goods plus freight, and import VAT on the duty-inclusive amount — the order customs uses, because getting it wrong understates your cost. Duty itself is a band, not a fake precision: the rate depends on the tariff line a customs officer assigns, so MurmMargin applies the band for the category the page itself declares and prints both edges. Every assumption the numbers rest on — VAT registration, payment fees, freight split — is written next to the figures at the same size. It remembers what this listing cost last time Come back in two weeks and it tells you the supplier quietly moved the price: "EUR 3.75 when you looked 14 days ago — EUR 4.20 now." Recorded on your machine, compared on your machine. It will never compare across a currency switch, because inventing an exchange rate would manufacture a price change out of thin air. What it will not tell you Whether the product will sell. That is not on the page, not computable, and not pretended — the panel prints an em-dash and the reason. It also will not read a price out of marketing text: only the machine layer counts, so a banner shouting a teaser price that is not in the listing data is ignored. Three permissions, and nothing runs until you click activeTab, scripting and storage. No host permissions, no background worker, no content script, no network requests of any kind. It reads the page you are on and remembers one price per listing so it can tell you what changed. Free. No account. Privacy Everything happens in your browser. https://murmtools.com/murmmargin-privacy Part of MurmTools — small research extensions that show their working. https://murmtools.com