Like other uncompressed sound files, WAV files consist of many thousands of individual samples of sound, like the frames of a film. A WAV's sample rate is usually expressed in kilohertz, and you can find the rate of a particular WAV file by viewing your operating system's information window about the file.
Find a WAV file's sample rate in Windows by right-clicking the file, then clicking "Properties." In the window that appears, look under "Audio Format" for a set of details including a number expressed in kilohertz (kHz): This is the sample rate.
Find a sample rate in Mac OS by clicking the file, holding down the "Command" key, and pressing "I." The Get Info window will appear; like Windows' Properties window, it will list the file's sample rate, either in kHz or hertz (Hz).
Find a sample rate in a Linux system similarly to the Windows method: Right click the file, then click "Properties." The sample rate information may appear in a different tab of the Properties box depending on your Linux distribution and version. If it doesn't appear in the main tab, look for an "Audio" or "More Info" tab.