Electric Field Strength Converter
Electric field strength is the force per unit charge, with the SI unit of the volt per meter (V/m), which is identical to the newton per coulomb (N/C). It is also commonly written in kilovolts per meter, volts per centimeter, or kilovolts per centimeter, the last being typical for dielectric breakdown figures. This converter reduces any of these to volts per meter as a base and converts out using exact length and prefix factors: 1 kV/m equals 1,000 V/m and 1 V/cm equals 100 V/m.
Electric field strength conversion
Base value (V/m) = input * factor(from unit)
Output = base value / factor(to unit)
1 kV/m = 1,000 V/m
1 V/cm = 100 V/m
1 kV/cm = 100,000 V/m
The volt per meter equals the newton per coulomb, because a volt is a joule per coulomb and a joule per meter is a newton. So V/m and N/C are interchangeable.
Electric field strength context
- The SI unit is the volt per meter (V/m), equal to the newton per coulomb (N/C).
- The dielectric strength of dry air is roughly 30 kV/cm at standard conditions.
- Field strength equals voltage divided by separation for a uniform field.
- 1 kV/cm equals 100,000 V/m, a common scale for high-voltage insulation.
- Electric field is a vector; this converter handles magnitude only.
Electric field strength: frequently asked questions
Why is V/m the same as N/C?
A volt is a joule per coulomb, so a volt per meter is a joule per coulomb per meter, which is a newton per coulomb (since a joule per meter is a newton). The two units are exactly equal.
How do I convert kV/cm to V/m?
Multiply by 100,000. A kilovolt is 1,000 volts and a centimeter is 0.01 meter, so 1 kV/cm equals 1,000 V divided by 0.01 m, which is 100,000 V/m.
What is the breakdown field of air?
Dry air breaks down (sparks) at roughly 30 kV/cm, or 3e6 V/m, at standard temperature and pressure. The exact value depends on humidity, gap geometry, and pressure.
Is electric field strength a vector?
Yes, the electric field has direction as well as magnitude. This converter handles only the magnitude; direction is unchanged by a unit conversion.
How does field relate to voltage?
For a uniform field between parallel plates, the field strength equals the voltage divided by the plate separation. So 100 V across 1 cm gives 10,000 V/m.
Official sources
- NIST Special Publication 811: Guide for the Use of the International System of Units.
- NIST Office of Weights and Measures: SI Units.
Reviewed by the CalculatorHub team, edited by James Graham, 17 June 2026. See our methodology.