Convert electric field strength between V/m, kV/m, V/cm, kV/cm and V/mm.
Electricity • 7 units
All 7 units on the Electric Field Strength Converter are defined against the Volt/meter (V/m), so each result is one conversion factor away from a single reference rather than the end of a chain of roundings.
The conversion this page is most often opened for is ready before you type anything: 1 V/m = 0.01 V/cm. Change either side and every row in the table recalculates with it.
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Conversions in this family are governed by the length unit rather than the voltage one, and the page's default pair shows why: 1 V/m is 0.01 V/cm, because the centimetre sits in the denominator and makes the number smaller rather than larger. The same inversion catches people moving to volts per millimetre, where 1 kV/mm is 1,000,000 V/m. Whenever a conversion here feels backwards, it is because the unit being changed lies underneath the division line.
American insulation datasheets add a unit that is not in the table but frequently sits beside it: volts per mil, a mil being one thousandth of an inch. One V/mil is about 39,370 V/m, or 39.37 kV/m — the volts-per-inch row scaled by a thousand. Dielectric strengths are commonly published this way, at a few hundred V/mil for common polymers, so comparing a US datasheet with a European one almost always requires this step before the two numbers can be set side by side.
Dielectric strength figures also depend on how the sample was tested, which limits how far any converted number can be trusted. Breakdown voltage does not scale linearly with thickness: a thin film tests at a higher V/m than a thick sheet of the identical polymer, and standard test methods pin down electrode geometry precisely because sharp edges concentrate the field and depress the result. A converted dielectric strength is a comparison figure obtained under a defined procedure, not a guaranteed ceiling for a particular part in a particular shape.
Quick reference — 1 Volt/meter (V/m) is equal to:
| Kilovolt/meter | kV/m | 0.001 |
| Volt/centimeter | V/cm | 0.01 |
| Kilovolt/centimeter | kV/cm | 0.00001 |
| Volt/millimeter | V/mm | 0.001 |
| Millivolt/meter | mV/m | 1,000 |
| Volt/inch | V/in | 0.0253999992 |
7 units of electric field strength, each a fixed multiple of the V/m. The table spans 100,000,000:1, from mV/m (0.001 V/m) to kV/cm (100000 V/m). Conversion is one multiplication into the base unit and one division out of it, with no lookup table and no approximation.
value_to = value_from × (factor_from ÷ factor_to)1 V/m = 1 V/m1 kV/m = 1000 V/m1 V/cm = 100 V/m1 kV/cm = 100000 V/m1 V/mm = 1000 V/m1 mV/m = 0.001 V/m1 V/in = 39.3701 V/mwhere:
Assumptions: Factors are exact definitions. Full double precision is carried internally and rounding is applied only for display.
Result25 V/m = 0.25 V/cm
Electric field strength is force per unit charge, expressed in volts per metre (V/m). It describes how steeply voltage changes across space rather than how much voltage exists, which is why the geometry of an insulator matters as much as its material.
The number worth remembering is the dielectric strength of air, roughly 3 MV/m at sea level. That single figure explains clearance distances on circuit boards, the shape of high-voltage insulators, and why sharp points spark first: field strength concentrates at small radii, so a corner reaches breakdown while a rounded surface at the same voltage does not. Volts per mil and kilovolts per inch persist in American datasheets, which is where most conversion errors in this area originate.