In physics and chemistry, the **Faraday constant** is the amount of electric charge of one mole of electrons.

It has the symbol F, and is given by

- ,

The value of F was first determined by weighing the amount of silver deposited in an electrochemical reaction in which a measured current was passed for a measured time. This value was used to calculate Avogadro's number. Research is continuing into more accurate ways of determining F, and thereby N_{A}. There are plans to use this value to redefine the kilogram in terms of a known number of atoms. [Source: NPL Annual Review 1999]

- F = 964 85.309 29 C/mol ± 0.028 945 6 C/mol [Horner's Physics Constants, 1999]
- F = 96 485.3415 C/mol ± 0.0039 C/mol [NIST, 2003, quoting CODATA, 1998]