A distinct purpose for every tool
Each calculator should solve a specific task and add useful context: units, a formula, a worked example, limitations, and relevant references. We do not create duplicate calculators simply to vary a keyword. Related measurements and options belong together when they help answer the same question. A regional page needs relevant differences in the task or source context.
Accuracy before expansion
New formulas must have a known-answer test and defined input boundaries. Changes to calculation logic must pass the full calculator test suite. Estimates are labeled, and uncertain inputs remain under your control.
Development and review
We use AI assistance in development and writing. Our methodology explains the checks and their limits. Automated tests are evidence for the examples tested; they are not a claim of professional review, certification or real-world product testing.
Sources and corrections
We prefer original standards, documentation, and technical references. References are described according to what they actually support, such as a conversion, product specification or method. They do not imply review or endorsement of this site. Time-sensitive fees or rates should be entered by the user instead of silently hard-coded. Contact CalcPatch with the calculator page, inputs, expected result, and calculation details.
When we update a page
We prioritize incorrect results, changed source facts, unclear instructions and useful improvements to existing tasks. Stable formulas do not need rewriting on a fixed weekly schedule. An update date, when shown, should reflect a meaningful change to that page. We do not change dates just to make unchanged content appear new.
Advertising
Advertising may eventually support these free tools. Advertisements must be clearly labeled, kept away from form controls, and must not change a result. No advertising network is currently connected to CalcPatch.