Calculator methodology and testing policy.
Fair Calcs publishes planning estimates, not guaranteed outcomes. This policy explains how formulas, changing external assumptions, browser behavior, and corrections are handled.
Formula validation
- Use standard published formulas or clearly described arithmetic.
- Keep full precision during calculations and round only for display unless cent-level solver logic requires otherwise.
- Check known-value examples, zero-rate cases, invalid inputs, and practical upper and lower boundaries.
- For minimum-price solvers, verify that the returned cent satisfies the target and the previous cent does not.
- Run browser checks across every generated calculator route and narrow mobile layouts.
External rates and marketplace rules
Marketplace fees and other changing rules require an official source, a visible review date, and a limitation explaining where the estimate may differ. Fair Calcs does not silently present a changing rate as permanent.
Automation and editorial review
Reusable code generates consistent page structure, validation, and metadata. Each published calculator still requires a working formula, editable inputs, page-specific limitations, and automated checks. Dates are changed only when formulas, sources, or editorial content are materially reviewed.
Privacy and corrections
Static calculator inputs remain in the browser unless you explicitly create a share link. Shared assumptions are stored after the URL fragment marker (#), which stays client-side and is not sent in the page request. When first-party interaction analytics is enabled, events record the calculator path and action name, never entered values or share-link fragments. Report a suspected formula or source issue to [email protected]; corrections are prioritized when they can change a decision.