About Convert Calc

Convert Calc is a free unit conversion tool designed to be fast, accurate, and trustworthy. Every conversion factor is sourced from published standards — primarily NIST SP 811, the SI Brochure (BIPM), and IEC 80000 — not crowdsourced or approximated.

Most online converters use cached conversion factors without source attribution. Convert Calc is different: every conversion formula is cited, every rounding decision is traceable, and every page explains when and why you'd use a particular conversion. If you find a discrepancy with our sources, we want to know.

Each converter page includes the conversion formula, a reference table, real-world examples, and answers to common questions. The source standard for each conversion factor is cited directly on the page.

Convert Calc works fast and reliably, anywhere and anytime. Converter data loads upfront with minimal external requests. We use Cloudflare Web Analytics for privacy-respecting usage insights (no cookies, no personal data). JavaScript is required for interactive conversions, but all formulas, tables, examples, and reference information remain visible and accessible.

Want to learn more? Explore how measurement systems work or start converting.