dBµV/m to V/m Converter

Radiated EMC work switches between two ways of writing the same electric field. Linear field strength in volts per metre (V/m, mV/m, µV/m) shows up in antenna theory, immunity test levels, and many near-field estimates. Logarithmic field strength in dBµV/m is what CISPR, FCC, and most EMI receivers print on a plot. A dBµV/m to V/m converter exists so you can read a limit line in one language and a datasheet or hand calculation in the other without dropping a factor of a million.

The conversion is not a change of physics. It is a change of reference: dBµV/m is 20 × log₁₀ of the field expressed in microvolts per metre. Engineers use it when they are comparing a receiver reading to an immunity level written in V/m, checking a customer spec that mixed units, or sanity-checking a spreadsheet that already converted antenna factor into dBµV/m.

To go from linear volts per metre to dBµV/m: dBµV/m = 20 × log₁₀(V/m × 10⁶). The 10⁶ term converts volts to microvolts before the decibel is taken. The inverse is V/m = 10^((dBµV/m) / 20) / 10⁶. One volt per metre is exactly 120 dBµV/m; 1 mV/m is 60 dBµV/m; 1 µV/m is 0 dBµV/m.

Because the scale is 20 log, a factor-of-two change in V/m is about 6 dB, and a factor of ten is 20 dB. That is why a 3 dB “almost fail” on a radiated plot is a much smaller linear change than it looks if you are used to voltage ratios on a scope.

Typical moments: you have a CISPR 32 Class B plot in dBµV/m and a customer asked for the peak in V/m; you are setting an RS103 or IEC 61000-4-3 field and the chamber software wants V/m while the procedure appendix listed dBµV/m; or you are converting a hand-calculated far-field estimate into the same units as the limit line before you decide whether a pre-scan is even worth booking.

This tool does not apply antenna factor, cable loss, or measurement distance. Those belong in the radiated field calculator and the distance-extrapolation converter. Use this page when the only job is unit translation between dBµV/m and V/m.