dBm to dBµV Converter

Convert between dBm and dBµV at any system impedance (50 Ω, 75 Ω, or custom).

Use this when: You have a spectrum analyzer or LISN reading in dBm or dBµV.

Reference only. Verify against your calibrated setup, antenna calibration data, and the applicable standard before making compliance decisions.

What a dBm to dBµV converter does

Conducted EMC measurements live in two instrument languages. Spectrum analyzers and many RF signal generators display power in dBm (decibels relative to 1 mW). EMI receivers and LISN plots usually display voltage in dBµV (decibels relative to 1 µV). A dBm to dBµV converter translates between those readings once you know the system impedance.

The conversion is not optional trivia. A 50 Ω LISN reading of 60 dBµV is not the same number of dBm as a 75 Ω video path at 60 dBµV. If you ignore impedance, you will invent a 3–6 dB error that looks like a real emissions problem.

The formula

dBµV = dBm + 10·log₁₀(Z) + 90, where Z is impedance in ohms. At 50 Ω the offset is 107 dB, so 0 dBm equals 107 dBµV. At 75 Ω the offset is about 108.8 dB. The inverse subtracts the same offset.

Use the impedance that matches the instrument setting and the LISN or terminator you actually connected—not the impedance you wish the standard used.

Frequently asked questions

Quick answers about using this calculator

How do I convert dBm to dBµV?

dBµV = dBm + 10·log₁₀(Z) + 90. At 50 Ω the offset is 107 dB; at 75 Ω it is about 108.8 dB.

Why does impedance matter for dBm to dBµV?

dBm is power relative to 1 mW; dBµV is voltage. The conversion depends on the load impedance (typically 50 Ω for RF, 75 Ω for video, or 600 Ω for audio).

What impedance should I use?

Match your measurement setup: 50 Ω for most spectrum analyzers and LISNs, 75 Ω for cable TV paths, or enter a custom value from your instrument settings.

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