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**

Many spectrum analyzer manufacturers use different bandwidth settings to specify their noise floor. For example TinySA‘s noise floor specifications are

*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

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