Here is a quick EC to PPM conversion chart. On the left hand side, you have EC or ms/cm values. The next 3 columns are the converted PPM values of the EC based on 3 different scales.
Most high-end meters will show EC as well as multiple PPM values. Most inexpensive meters will only display PPM and usually in the 500 scale. It is important to read the owners manual of whatever meter you are using and make sure you know what scale and values are being displayed.