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.
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.
Sources and corrections
We prefer original standards, documentation, and technical references. A cited reference supports the method described; it is not a claim of review or endorsement. Time-sensitive fees or rates should be entered by the user instead of silently hard-coded. Keep these details when checking a result.
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.