There are multiple ways a capacitor can indicate its capacitance. Larger capacitors often have their capacitance, tolerance and maximum voltage written on the side. Smaller capacitors often use a code consisting of three numbers and sometimes one letter.
You can use this calculator to calculate the capacitance and tolerance of a capacitor.
The capacitance in picofarad (pF) is equal to the first two digits multiplied by ten to the power of the third digit: C = AB·10 C . Some capacitors contain the letter R, which represents the decimal point. The capacitance in pF is equal to all digits linked together with a decimal point on the location of the R in this case. The letter at the end indicates the tolerance. These values can be found in the table below.
We have a capacitor with the code 156J. The capacitance is 15·10 6 pF = 15μF. The tolerance for J is 5%.