Privacy

Summary. Margin Ruler provides account-free, browser-based calculations with transparent formulas. Inputs are used to return estimates; vendor links are independent third-party destinations and may be commissionable.

What we process. When you use this site, Cloudflare (our infrastructure provider) processes standard request metadata — IP address, country, user agent, request path, and timestamps — for security, DDoS protection, and reliability. This processing occurs on Cloudflare's network under their privacy policy. We do not receive or store individually-identifiable request logs beyond Cloudflare's standard aggregate analytics.

Calculator inputs. Calculator inputs you enter are processed in your browser and are not used for advertising, profiling, or tracking. If you choose to create a shareable estimate link, the estimate inputs and result are stored temporarily to enable link retrieval. This stored data is not linked to your identity and is not used for any purpose beyond reopening the shared link.

AI assistant connections (MCP). If you use Margin Ruler through an AI assistant that supports the Model Context Protocol, the assistant sends the calculator inputs to our server, which computes the result and returns it. We do not store those inputs. For each call we record operational metadata (the tool name, response time and status, a result band, a coarse user-agent category and a truncated IP prefix) to keep the service reliable. Your assistant provider's privacy policy governs what it sends to us.

Browser extension. The Margin Ruler: FBA Profit for Amazon Sellers browser extension runs only on Amazon.com (US marketplace) product pages. It reads the price, package size, weight and category shown on the product page you are viewing and does its calculations in your browser. The cost, category and FBA fee you type are saved in your browser's extension storage so they reappear when you return to that product; they are not sent to us, and removing the extension deletes them. To get Amazon fee rates, the extension requests Margin Ruler's public fee schedule at most once every 12 hours, without cookies or any page content; Cloudflare processes that request's standard metadata as described above. The extension has no analytics, advertising or affiliate links and does not change Amazon's content or links; it only adds its own panel. If you click its "Full breakdown" link, the price, cost, shipping weight, size tier and category travel in the part of that link after the "#", which your browser does not send to our servers or to anyone else; the Margin Ruler calculator reads them in your browser to fill in the form and then removes them from the address bar. The link also carries src=fba_extension, which tells us only that the visit came from the extension; it contains nothing about you or the product.

Third parties. When you click a vendor link, you are navigating to an independent third-party site under their privacy policy. We do not share data with affiliate partners in connection with your click — the click itself carries no personal data from us to the destination.

Link-back from embedded calculators. A site owner who embeds Margin Ruler calculators with the WordPress plugin can turn on an optional link back to the full tool. If you follow that link, Margin Ruler may set one first-party cookie named __Host-mr_pump for seven days. It holds a short code for that site's installation, not for you, so we can count visits from that installation and later clicks on partner links. It contains no calculator inputs, names, email addresses, or advertising profile, and it is not shared with partners.

Advertising. This site may display advertising from third-party ad networks. If display advertising is active, the ad network may set cookies for ad delivery and measurement under its own privacy policy. We do not load behavioral advertising SDKs beyond what is required for ad delivery. We do not operate retargeting or cross-site profiling.

California residents (CCPA). We do not sell personal information. We do not share personal information for cross-context behavioral advertising. You have the right to know what personal information (if any) we hold about you, and to request deletion. Contact us at the address below to exercise these rights.

EEA/UK residents (GDPR/UK GDPR). This service is not currently directed at or available to users in EEA or UK jurisdictions. If you are accessing this page through a proxy or VPN, note that the service is geo-restricted and not intended for EEA or UK users. For questions about data processed in connection with any incidental access, contact us at the address below.

Data retention. We do not retain personal data. Cloudflare retains request logs per their standard retention schedule. Aggregate analytics are retained indefinitely in non-identifiable form. Shareable estimate payloads (created only when you explicitly use the share feature) are stored temporarily and are not linked to your identity.

Contact for privacy requests: legal@marginruler.com