Vapor Pressure Calculator

Vapor Pressure (Antoine)

Antoine equation estimate; P returned in mmHg (common Antoine units).

2026-05-06T10:07:27.286Z
°C

Vapor Pressure (P)

23.6864 mmHg

log₁₀(P) = A − (B / (C + T))

About Antoine Equation

The Antoine equation is a semi-empirical correlation that describes the relationship between vapor pressure and temperature for pure substances. The constants A, B, and C are specific to each substance and temperature range.

How to use

Provide Antoine constants (A, B, C) appropriate for the substance and the temperature range, then read the vapor pressure in mmHg.

Example

For water at 25°C using typical Antoine constants, the calculator returns an estimate for vapor pressure.

FAQs

Q: Units? A: Output is mmHg if constants are for that unit. Q: When to use Antoine? A: Use within the validity temperature range for the constants.

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