The Electronic Industries Alliance (EIA) provides specific standards for resistor values. Availability of resistor value is also determined by the size of tolerances that is known as E series. The number following the "E" specifies the number of logarithmic steps per decade.

The series are as follows:
E6 20% tolerance (now seldom used)
E12 10% tolerance
E24 5% tolerance
E48 2% tolerance
E96 1% tolerance
E192 0.5, 0.25, 0.1% and higher tolerances