Enter the total signal (volts) and total noise (volts) into the calculator to determine the SNR (signal-to-noise ratio).

## SNR Formula

The following formula is used to calculate the signal-to-noise ratio (SNR).

SNR = 20*log(S / N)

SNR = 20*log_{10} (S / N)

- Where SNR is the signal to noise ratio (decibels, dB)
- S is the signal (volts)
- N is the noise (volts)

The units for signal and noise could be different, for example, millivolts, as long as the units are the same for each variable.

## SNR Example Problem

How to calculate SNR?

**First, determine the signal strength.**In this example, the signal strength is measured to be 45 volts.

**Next, determine the noise strength.**For this problem, the noise is measured to be 3.5 volts.

**Finally, calculate the signal-to-noise ratio (SNR).**Using the formula above, the SNR is calculated to be:

SNR = 20*log_{10}(S / N)

SNR = 20*log_{10}(45 / 3.5)

SNR = 22.182