Locate identifying marks on the surface of the capacitor. Information such as capacitance and product code are visible. In some cases this information is stamped into the capacitor, as opposed to printing, making it difficult to see without close inspection.
Examine the information and determine whether a capacitance rating is given. This rating is shown in terms of "Farads," often shortened to just "F," with a value next to it. This value identifies the capacitor by its capacitance.
Examine the code given on the capacitor to identify it. In the absence of a direct identification, a code is often given that aids in determining the capacitance. This code is a three-digit number. The first two numbers give the first two digits of the capacitance. The final number shows how many zeros follow the first two digits. For example, a code of 121 is interpreted as 12 with one 0 after it. Thus the code identifies a 120pF (pF short for picoFarad) capacitor.