**Hz** is a unit of Frequency. **dB** or deciBel is used to express the ratio of two power values on a logarithmic scale.

In general, Hz cannot be converted to dB as there is no equivalence between frequency and amplitude. However the ratio of two frequencies can be expressed on a log scale as dB-Hz.

This tool converts Hertz (**Hz**) to deciBel-Hertz (**dB-Hz**)

**Background**

**Hz** is a unit of frequency and is equivalent to cycles per second.

deciBel or **dB **represents a ratio of two values. Typically the two quantities are Amplitude or Power Levels. The units are the same and hence dB is simply a ratio.

**dB-Hz or dB (Hz) is the bandwidth relative to 1 Hz**

A linear number can be converted to its dB equivalent using this calculator. the formula is **P _{dB} = 10*Log_{10}(P_{linear})**.

Similarly,

**dB-Hz = 10*Log _{10}(Hz)**

dB has a logarithmic nature. The benefit of using dB is that a very large (or very small) ratio can be conveniently represented by a small number. For example, 1000000000 Hz = 90 dB-Hz.

**Example Calculations**

**100 Hz** can be represented as **20 dB-Hz**.

**1000 Hz** is equivalent to **30 dB-Hz**.

**Notes**

[1] **dB-Hz** should not be confused with **dBm/Hz** which is the power spectral density. PSD can be converted to **dBm**.

[2] Carrier-to-Noise Density ratio also has the units dB-Hz. Carrier power is expressed in dBm while Noise Density has units dBm/Hz.