Editorial policy

Who is responsible

Sunit Kumar, the founder and editor of Zetta Calculators, is responsible for every calculator and guide on the site. Questions and corrections go to the same place: the contact form or hello@zettacalculators.com.

What this policy covers

This policy applies to the calculators and the guides. It applies in full to every page updated since October 2026, starting with the math, education and date and time calculators, which are the focus of the site. Older pages are being reviewed against it. Pages outside that focus that have not been reviewed are marked so that search engines do not index them.

Sources

Formulas, rules and reference figures come from primary sources: the organization that defines the rule, publishes the data or makes the product. For example:

• Standards and definitions: the Common Core State Standards for school math, and NIST for units of measurement (1 pound is exactly 0.45359237 kilograms).
• Government rules: the U.S. Office of Personnel Management's federal holiday schedules and the law they rest on, 5 U.S.C. 6103.
• Official publishers of a test or tool: the ACT/SAT concordance tables published by ACT and College Board, CFA Institute's exam calculator policy and the Texas Instruments guidebook for the BA II Plus.
• Peer-reviewed research: for example, Brysbaert's 2019 review of 190 reading-rate studies for average reading speeds.

Each updated page lists its sources, with links, at the end of its how-to section. Other calculator sites, forum answers and statistics that cannot be traced to their origin are not used as evidence. If a figure cannot be confirmed in a primary source, it is left out, or the page says plainly that it is an estimate, as the word-to-page calculator does for words per page.

Numbers and worked examples

• Every worked example is produced by running the calculator on the page with the inputs shown. When the text quotes a result, it quotes the calculator's output exactly.
• The arithmetic in each step-by-step example is checked separately, so a page cannot pass on the strength of a result alone.
• Before a page goes live, every claim it makes about the tool, such as "gives no result" or "rounds to six decimal places", is checked against what the tool actually does.
• The calculators themselves are tested as described in How we test our calculators.

Limits and advice

Each updated calculator page has a section on what the tool does not do. Where a rule differs between schools, employers or countries, such as attendance requirements or which calculators an exam allows, the page points to the official rule and says that local policies can differ. The calculators are for education and everyday planning, not financial, medical, legal or tax advice; see the disclaimer.

Independence

The site carries no advertising, no affiliate links and no sponsored content, and nobody pays to be mentioned or to influence a result. Products and services are named only when a page needs them, for example a calculator model that an exam allows, and never in exchange for payment. We use Google Analytics to count visits, as the privacy policy explains; the numbers you type into a calculator are not sent to us.

Updates

Every calculator and guide shows a "Last updated" date. It changes only when the content changes: a new date always means the page itself is different, never a new date on the same text. When a source publishes a new version, such as next year's federal holiday schedule or a revised score concordance, the calculators that depend on it are updated and retested.

Corrections

If you think a result or a statement is wrong, please tell us, with the inputs you used if it is a calculator. Every report is checked. A confirmed error is fixed, the fix is tested, and an entry with the date and what changed is added to the corrections log. Results are never changed silently.

Last updated: October 16, 2026