How is electric field strength calculated from force and charge?

The strength of an electric field ($E$) at any given point in space is defined as the Coulomb force ($F$) exerted per unit of positive electric charge ($q$) placed at that point.1

This relationship is expressed by the following equation:
$$E=\frac{F}{q}$$

In this context, the electric field is considered a vector quantity, meaning it possesses both magnitude and direction. The direction of the electric field is defined as the direction of the force that would be exerted on a positive test charge.12

Because the electric field strength depends on the source charge rather than the test charge, the quotient $F/q$ remains constant at any specific point in space, even if the magnitude of the test charge is varied. In the SI system, this value is measured in newtons per coulomb (N/C), which is equivalent to volts per metre (V/m).12