This tool converts from crystal oscillator stability in terms of parts per million (ppm) to the equivalent frequency variation (Hz/kHz/MHz/GHz)

## Formula

The frequency variation **df** on either side of the center frequency **F** is given by

**df = F*ppm*10 ^{-6}**

The maximum and minimum frequency are given by

**Fmax = F + df**

**Fmin = F – df**

## Example

The 32 MHz oscillator has a frequency stability of +/- 25 PPM.

The oscillator can be used as a reference clock with a phase locked loop to generate a frequency of 1 GHz.

Enter these numbers into the calculator above to calculate a frequency variation of **+/- 25 kHz**. The minimum and maximum frequencies generated are **999.975 MHz** and **1000.025 MHz**, respectively.