About Vacuum Engineering Tools

Vacuum Engineering Tools is a free collection of calculators, converters and reference data for vacuum technology. The goal is simple: give engineers, technicians and students fast, correct answers with the formulas shown, on any device.

Methods and sources

Unit conversions use exact SI definitions (1 Torr = 101,325/760 Pa, 1 psi = 6,894.757 Pa, 1 inHg = 3,386.389 Pa).
Water vapor pressure uses the IAPWS Wagner–Pruss formulation (liquid) and the Murphy–Koop equation (ice).
Other liquids use published Antoine coefficients (see the NIST Chemistry WebBook) within their stated temperature ranges.
Vacuum ranges follow ISO 3529-1, with extreme-high vacuum as a commonly used extension.
Conductance formulas are the standard long-tube equations for air at 20 °C found in vacuum technology handbooks such as Jousten and O’Hanlon & Gessert.

Limitations

Results are engineering estimates. Real systems are affected by outgassing, leaks, temperature, gas composition and component tolerances. Always verify safety-critical or high-value designs against manufacturer data.

Ad-free, open to partnerships

We try to keep Vacuum Engineering Tools free of ads so the tools stay fast and distraction-free. We are, however, interested in partnerships with vacuum equipment manufacturers, distributors and service providers that fit this goal. If that sounds like you, get in touch at info@vacuumpumps.xyz.

References & further reading

W. Wagner & A. Pruss. The IAPWS Formulation 1995 for the Thermodynamic Properties of Ordinary Water Substance for General and Scientific Use. J. Phys. Chem. Ref. Data 31, 387 (2002). Reference equation of state for water.

IAPWS. SR1-86(1992): Revised Supplementary Release on Saturation Properties of Ordinary Water Substance. International Association for the Properties of Water and Steam. Saturation vapour pressure equation used for liquid water.

D. M. Murphy & T. Koop. Review of the vapour pressures of ice and supercooled water for atmospheric applications. Q. J. R. Meteorol. Soc. 131, 1539 (2005). Sublimation pressure over ice below 0.01 °C.

NIST. NIST Chemistry WebBook, SRD 69. National Institute of Standards and Technology. Antoine coefficients and phase-change data for solvents.

ISO/TC 112. ISO 3529-1:2019 Vacuum technology — Vocabulary — Part 1: General terms. International Organization for Standardization (2019). Official definitions of the vacuum ranges.

ISO/TC 135. ISO 20484:2017 Non-destructive testing — Leak testing — Vocabulary. International Organization for Standardization (2017). Standard terms and units for leak rates.

BIPM. The International System of Units (SI Brochure). Bureau International des Poids et Mesures. Definition of the pascal and SI prefixes.

A. Thompson & B. N. Taylor. NIST Special Publication 811: Guide for the Use of the International System of Units. National Institute of Standards and Technology. Conversion factors for Torr, psi, inHg and other legacy units.

K. Jousten (ed.). Handbook of Vacuum Technology, 2nd ed.. Wiley-VCH (2016). Standard reference on gas flow, conductance, pumps and gauges.

J. F. O’Hanlon & T. A. Gessert. A User’s Guide to Vacuum Technology, 4th ed.. Wiley (2023). Practical design of vacuum systems, pump-down and outgassing.

CERN Accelerator School. CAS Vacuum in Accelerators, Platja d’Aro, Spain, 2006 — proceedings (CERN-2007-003). CERN (2007), free to read. Lectures on gas dynamics, conductance, pumps and outgassing.

CERN Accelerator School. CAS Vacuum for Particle Accelerators, Glumslöv, Sweden, 2017 — proceedings. CERN, free to read. Up-to-date lectures on materials, pumps, gauges and leak detection.