Privacy
Short version: the calculators run entirely in your browser. Your product costs, supplier prices and margins never leave your device, because there is nowhere for them to go.
What stays on your device
Every calculation happens in JavaScript on the page. Nothing you type is transmitted to a server, logged, or stored anywhere we can read. That is an architectural fact rather than a policy promise — a static site has no backend to receive it.
Two things are stored locally, in your own browser:
- Your last inputs per calculator, so a return visit does not mean retyping your dimensions.
Stored in localStorage under keys beginning
shipmargin:. - Your light or dark theme choice.
Clearing your browser storage removes both. Neither is ever sent anywhere.
Shareable links
Calculator inputs are encoded in the page URL so you can share a scenario. That URL is built in your browser and only goes wherever you choose to send it. Worth saying out loud: if you paste a link into a public forum, the numbers in it are visible to anyone who reads it. That is the point of the feature, but it matters if the figures are commercially sensitive.
Analytics
If analytics are enabled they are privacy-preserving and aggregate: page views and referrers, no cookies, no cross-site tracking, no individual profiles, no advertising identifiers. We want to know which calculators get used so we know what to build next. That is the whole requirement.
Third parties
We embed nothing. No third-party fonts, no tag managers, no chat widgets, no advertising scripts. The Content Security Policy on this site blocks external scripts outright, which means even a compromised dependency could not send anything out.
Outbound links to carriers, marketplaces and government tariff sites take you to those sites, which have their own policies.
Your rights
Because we hold no personal data about you, there is nothing to access, export or erase on our side. If you have emailed us, that email exists in an inbox and you can ask us to delete it.
Questions: contact us.