Methodology
How our calculator results are produced
Shared conventions for formula disclosure, input handling, rounding, validation, verification, and corrections. A calculator page's own notes take precedence when its method differs.
Who maintains the calculators
Simple US Tools maintains the site and its calculator explanations. We do not claim that the calculators have been independently audited or reviewed by a financial, tax, accounting, or investment professional. Calculator results are planning estimates, not professional advice.
What the pilot covers
The detailed transparency blocks currently cover the pay raise, subscription cost, and break-even calculators. For these tools, inputs are processed in the browser and are not submitted to a Simple US Tools backend. Each block identifies the formula, inputs, assumptions, display rounding, and important exclusions for that calculator.
Formula and rounding conventions
Calculations use the numeric values entered into the tool and keep normal JavaScript numeric precision until a result is formatted for display. Currency may be shown to the nearest dollar or nearest cent, depending on the result. Percentage displays may also use a limited number of decimal places. When a calculator intentionally changes the mathematical result—such as rounding break-even units up to a whole sellable unit—the page discloses that rule directly.
A worked example is an illustration of the stated formula. It does not establish that the same assumptions fit every user or real-world situation.
Validation and edge cases
The pilot calculators reject missing, nonnumeric, or out-of-range inputs where the current formula would be undefined or misleading. Examples include a nonpositive current salary, a negative subscription price, and a variable cost that is equal to or greater than the selling price. Validation limits are part of the tool, not a judgment about what values are realistic for every user.
Verification and testing
Before a release, the site is checked for lint and type errors and built in production mode. Known examples and boundary inputs can be checked in the rendered calculators. Automated formula coverage varies by tool; we do not present a successful build as proof of financial accuracy or claim that every possible input has been tested.
Corrections
If a formula description does not match a result, or an input produces an unexpected outcome, please include the calculator name, inputs, expected result, and observed result when you contact Simple US Tools. We use that information to reproduce and correct issues without needing private financial details.