Editorial Policy

How calculators are built

Each calculator uses a documented formula. The formula is written as a small function with automated tests that cover normal values and edge cases such as zero, negative numbers and empty fields.

How content is written

Articles explain what the calculator does, show the formula, walk through a worked example and list common mistakes. We write for readers first and avoid padding.

Sources and reference data

When a tool relies on outside data, such as state filing fees or nutrition values, we use official or primary sources where possible and record the source link and the date the figure was last verified. If a value has not been verified, we say so instead of guessing.

Updates and corrections

Pages show a "last updated" date. We review reference data regularly and whenever a reader reports a change. To report an error, use the contact page.

Advertising and independence

Ads help pay for the site. Advertisers do not influence formulas, results or article content.