Oscillators and other frequency control devices specify their frequency variation in units of parts per million (ppm). Use this calculator to convert ppm to Hz (left column), or Hz to ppm (right column). The equation for this relationship is,
where ppm is the peak variation (expressed as +/), is the center frequency (in Hz), and is the peak frequency variation (in Hz).
Enter numbers below as integers, decimals, or use scientific notation (for example, enter 1500 as 1500, 1.5e3, or 1.5E3).

For example, 100 ppm of 100 MHz represents a variation in frequency of 10 kHz. The maximum and minimum
frequencies are therefore 100.01 and 99.99 MHz, respectively.
The change in period between these two frequencies is 2 ps (that is, 1/99.99MHz  1/100.01MHz). 
For example, if a center frequency varies from 100 MHz to 100.01 MHz, this 10 kHz frequency variation represents 100 ppm.
