PRIVACY

Your setup
stays with you.

Updated September 11, 2026.

Calculation inputs

Reel capacity, line lengths, diameters and uncertainty assumptions are processed in your browser. The calculator does not send these inputs or your generated reports to a server. There is no account, upload or model API.

Saved setup and exports

Setup A is kept only in the current page's memory. Reloading or closing the tab clears it. A copied report goes to your device's clipboard; a downloaded report is a local text file. You control any subsequent sharing.

Basic usage measurement

The site records page views, task starts, valid calculations, report export requests and return visits. It stores a random identifier in sessionStorage for the current browser tab and a last-visit date in localStorage to recognise a later-day visit within 60 days. These values can be cleared through your browser settings. Events include the referring hostname, without its path or query. Our measurement database does not store IP addresses, browser user-agent strings or input values. Those events do not include the numbers entered, report text or a reel identity. Hosting and measurement services may process ordinary request metadata, such as the page requested, time, browser information and IP address, to deliver and protect the service. Input values are not placed in page URLs.

This page describes the calculator's data boundary. Measurements count interactions, not whether a reel was physically filled or whether an estimate was accurate.

External references

Method references open third-party sites with their own privacy policies. Spool Ledger does not load third-party fonts, advertisements, embedded calculators or libraries.