This tool converts from VRMS (root-mean-square voltage) or simply Volt to dBV (dB Volt).
To use the calculator enter the voltage value and use the drop down menu to select units: Volt, Millivolt, Microvolt or Nanovolt.
Formula
dBV = 20*Log10(VRMS/1V)
Background
dBV stands for deciBel relative to 1 Volt.
While it’s often not stated explicitly, this is 1 Volt RMS (Root-mean-square*) and not average, peak or peak-to-peak. Using the tool above: 1 Volt is equivalent to 0 dBV and 2 Volt is equivalent to 6.02 dBV.
Based on the definition of RMS voltage below, we can see that it is a positive quantity greater than or equal to zero.
VRMS = √(1/n)(V12 +V22 + … + Vn2)
For values of VRMS greater than 1, the equivalent value of dBV will be positive. If VRMS is less than 1, the equivalent dBV will be negative.
The exception is VRMS=0 where the equivalent dBV is infinitesimally small or -∞.
Note there is no reliance on impedance or resistance in the formula.
What’s the difference between dB and dBV?
deciBel or dB represents a ratio of two amplitude or power levels. It provides a measure of how large one number is relative to another. A power ratio of 100 for example is equivalent to 20 dB. The dB scale presents a convenient way to represent both very large and very small numbers. It’s used by engineers in various fields such as Radio Frequency, Optical and Audio.
DeciBel Volt or dBV represents an absolute quantity. The reference in this case is 1 Volt. As with dB, it is used to represent very large and small numbers.
Where is dBV used?
dBV is used in the world of Audio. It is consistent with measures for sound intensity and the Log scale is more representative of how the human ear responds to sound.
*RMS voltage can be calculated using a closed form expression for certain waveform types or a sequence of measured values.
Related Calculators
- dBV to dBu – dBV uses a 1 Volt reference, while dBu uses a 0.775 Volt reference