There are three types of tariffs: specific, advalorem, and compound. Specific tariffs are measured in accordance with a physical unit of measurement, such as on a per-ton, per-bushel, or per-meter rate, and are specified at a particular monetary value. Ad-valorem tariffs are measured on the value of the goods and are levied as a percentage of that value. Finally, Compound tariffs are a combination of ad-valorem and specific.