About SellerCalcs

SellerCalcs is a set of free, browser-based tools for people who sell things online: pricing calculators for markup and margin, advertising calculators for ROAS and cost per acquisition, cost accounting for COGS, and the shipping maths that decides whether a product is actually profitable after freight.

The second half of the toolbox handles the logistics paperwork that eats afternoons: CBM and dimensional weight from carton dimensions, air freight chargeable weight, import duty, landed cost per unit, and generators for the packing list and commercial invoice a customs clearance needs.

Every calculation runs locally in your browser. Costs, prices, shipment values and customer details you type are never uploaded, stored or transmitted, there is no sign-up, and nothing is behind a paywall or an email form.

The guides explain the arithmetic and the conventions behind the numbers — the markup-to-margin conversion, the chargeback ratio card networks enforce, how CBM is billed, and what belongs in landed cost — so results can be checked and applied rather than simply trusted.