Editorial Policy & Methodology
This page explains how CalcEagle calculators and articles are created, tested, reviewed and corrected.
Choosing formulas and sources
We start from the standard, published method for each calculation. Wherever possible we rely on primary sources: US government agencies (for example NIST, OPM and the IRS), court rules, university extension services and textbooks, standards bodies, and manufacturer technical data sheets. Each calculator page lists the sources it relies on under Sources and references.
When sources disagree, or when a published figure depends on assumptions (such as a waste factor or a typical density), the page says which value we use and lets you change it where that makes sense.
How calculators are tested
- Separate formula code. The math lives in its own module, apart from the page design and the article text. Editors cannot change formulas from the admin panel.
- Independent test cases. Expected answers are worked out separately — by hand, with exact arithmetic, or from published worked examples — and compared with the calculator automatically.
- Edge cases. Tests cover zero, negative and very large values, rounding, leap years and month-end dates, and inputs that make a formula undefined (such as dividing by zero). In those cases the calculator explains the problem instead of showing a misleading number.
- Browser checks. Each calculator is exercised in a real browser at desktop and phone widths, including error messages.
Writing and review
Articles explain what the tool does, how to use it, the formula, a realistic US example, how to read the result, its limitations and common mistakes. Drafts may be prepared with the help of software tools, including AI writing assistance; formulas and numbers are verified with the tests and sources described above before publication.
Every calculator shows the date it was last reviewed. Pages whose rules or data can change — such as legal deadlines, holiday schedules or game mechanics — are scheduled for more frequent review.
Limits of our tools
Calculators give estimates based on the inputs and assumptions shown. They are not a substitute for professional advice. Tax rules, court rules and product specifications vary by state, court and manufacturer.
Corrections
If you believe a result or statement is wrong, please contact us with the page, the inputs you used and what you expected. We investigate every report. Confirmed errors are fixed promptly and the page's review date is updated.
Advertising and independence
CalcEagle does not accept payment to change calculator results or rankings of products. If we add advertising or affiliate links in the future, they will be clearly labeled and will not affect calculations.