Antoine (aprox)
- Created by
- Renato Passos, Eng. de Software
- Reviewed by
- Renato Passos, Eng. de Software
Last updated: Apr 18, 2026
About this calculator
The Antoine Vapor Pressure Calculator is an online tool that uses the Antoine equation to estimate the vapor pressure of a substance at a given temperature. The Antoine equation is an approximation that relates the vapor pressure of a substance to its temperature, and is widely used in various fields of chemistry and engineering.
The Antoine equation is given by log P = A − B/(C+T), where P is the vapor pressure, T is the temperature in degrees Celsius, and A, B, and C are substance-specific constants. These constants are determined experimentally and are tabulated for various common substances.
The Antoine Vapor Pressure Calculator is useful in various situations, such as in the design of chemical process equipment, simulation of unit operations, and analysis of thermodynamic properties of substances. However, care should be taken with the temperature and pressure range for which the equation is valid, as well as with the accuracy of the constants used.
It is essential to remember that the Antoine equation is an approximation and may not be accurate for all substances or temperature and pressure conditions. Furthermore, the calculator does not replace the need for precise experimental data and validation in critical cases.
Frequently asked questions
What units are used in the calculator?
The vapor pressure is calculated in units of pressure (e.g., Pa, kPa, mmHg, etc.), and the temperature is in degrees Celsius.
What are the limitations of the Antoine equation?
The Antoine equation is an approximation and may not be accurate for all substances or temperature and pressure conditions. Additionally, the constants A, B, and C must be known for the substance in question.
How do I obtain the constants A, B, and C for a specific substance?
The constants A, B, and C can be obtained from tables of thermodynamic properties of substances, found in physical chemistry textbooks or online databases.
Can I use the calculator for substances that are not listed?
Yes, as long as you know the constants A, B, and C for the substance in question. However, the accuracy of the calculation depends on the accuracy of these constants.