Enter the current, cross-sectional area, free charge density, and charge into the calculator to determine the electron velocity.

Electron Velocity Formula

The following equation is used to calculate the Electron Velocity.

EV = I / (n*q*A)
  • Where EV is the electron velocity (m/s)
  • I is the current (amps)
  • n is the free charge density (1/m^3)
  • q is the charge (-1.60*10^-19 C)
  • A is the cross-sectional area (m^3)

What is an Electron Velocity?


The electron velocity is a measure of the average linear speed of an electron through a wire.

How to Calculate Electron Velocity?

Example Problem:

The following example outlines the steps and information needed to calculate the Electron Velocity.

First, determine the current. In this example, the current is found to be 30 amps.

Next, determine the free charge density. For this problem, the free charge density is found to be 5 *10^28 e-/m^3..

Next, determine the charge. In this case, the charge is measured to be -1.60*10^-19

Next, determine the cross-sectional area. For this problem, this is 5m^2.

Finally, calculate the Electron Velocity using the formula above:

EV = I / (n*q*A)

EV = 30 / ((5*10^28)*(-1.60*10^-19)*5)

EV = -7.5e-10