This tool converts Noise Spectral Density with units **nV/rt(Hz)** or **nV/√(Hz)** to **V _{RMS}**.

**Formula**

**μVrms = nV/√(Hz) * √(BW _{kHz} * 1.57)**

**Background**

The following graph shows a plot of input voltage noise vs frequency for an operational amplifier.

Between 200 Hz and 1 MHz, input voltage noise is approximately 6 nV/√(Hz). The value at any specific frequency can be converted to its equivalent dBm/Hz value.

**Application Examples**

Using the input voltage noise of **6 nV/√(Hz)** for this op amp. The value of RMS noise over a **100 kHz** bandwidth is **2.37 μVRMS**.

This calculation uses a 1-pole filter with an equivalent noise bandwidth of 1.57. If we assumed a brick wall filter, this value would be 1. In that situation you could verify these results using the following calculators to go from VRMS to nV/rt(Hz)