dBm/Hz also called Power Spectral Density, is the amount of power in dBm per Hertz of bandwidth.
To convert dBm/Hz to dBm, enter the value and desired bandwidth in the calculator below.
The tool will calculate the power over this bandwidth and provide a value in both dBm and Watt.
Use this next calculator to convert from dBm to dBm/Hz. Enter the value and bandwidth
What is dBm/Hz used for?
The noise floor of a spectrum analyzer is specified in dBm/Hz. It’s the power of the signal measured in a 1 Hz resolution bandwidth. The measurement is normalized to 1 Hz.
The lower this value, the more sensitive the analyzer. The lowest noise floor that can be measured is -174 dBm/Hz.
Applications of this calculator
Compare Spectrum Analyzer Noise Floor
Lowest discernible signal using a resolution bandwidth of 30 kHz of -102 dBm
The dBm to dBm/Hz calculator can be used to convert this to -147 dBm/Hz.
This can be compared with the noise floor of a Siglent Spectrum Analyzer which is more sensitive with a value of -161 dBm/Hz.
Convert between two different Resolution Bandwidths
Let’s say you want to convert a measurement that was made in a 30 kHz resolution bandwidth to 1 MHz resolution bandwidth.
- Use the second calculator to normalize from dBm/ 30 kHz to dBm/Hz
- Then enter this number in the first calculator along with the desired bandwidth of 1 MHz. This will convert from dBm/Hz to dBm/ 1 MHz