Terms of Use

Water Vapor Pressure provides free, browser-based vapor-pressure calculations. The results are computed on your device from published equations and validated against the IAPWS-95 standard.

Accuracy & engineering use

We work hard to make every formula correct and to flag when an input falls outside a formula’s validated range. Even so, the service is provided “as is,” without warranty of any kind. You are responsible for verifying any value before relying on it for engineering, safety, regulatory, or commercial decisions. For critical work, cross-check against the primary standard (IAPWS-95).

Attribution & affiliation

Reference values are based on IAPWS R6-95(2018). Water Vapor Pressure is not affiliated with, endorsed by, or sponsored by IAPWS, NIST, ASHRAE, or any standards body. The underlying equations and physical constants are scientific facts and are not copyrighted; published table layouts and documents remain the property of their authors and are not reproduced here.

Limitation of liability

To the fullest extent permitted by law, Water Vapor Pressure and its author are not liable for any damages arising from the use of, or inability to use, this service, including any decision made on the basis of a computed value.