About ConversionCalculator.net
ConversionCalculator.net is a free unit conversion tool covering 19 categories and 64 direct conversion pairs, with more added over time. Every formula on the site is sourced from NIST SP 811, Appendix B, the standard US reference for exact unit conversion factors, and the source is shown directly on each conversion page rather than hidden behind the result.
How the tools work
Each converter runs entirely in your browser. Values you enter aren't sent to a server or stored anywhere; the calculation happens locally using the formula shown on that page.
Methodology
Conversion factors are checked against NIST SP 811, Appendix B and, for SI unit definitions, the BIPM SI Brochure (9th edition, 2019). Where a factor is an exact defined constant (such as 1 inch = 2.54 cm), that's stated plainly rather than presented as a rounded approximation.