Inductor codes

Small inductors often use a numeric code to indicate the inductance. This code consists of thee numbers and sometimes an additional letter.


You can use this calculator to calculate the inductance and tolerance of an inductor.


The inductance in microhenry (μH) is equal to the first two digits multiplied by ten to the power of the third digit: C = AB·10 C . Some codes contain the letter R, which represents the decimal point. The inductance in μH 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.

letter tolerance letter tolerance
A 0.05nH H 3%
B 0.1nH J 5%
C 0.25nH K 10%
D 0.5nH L 15%
E 0.5% M 20%
F 1% V 25%
G 2% N 30%
Z +80% -20% - -


We have an inductor with the code 332F. The inductance is 33·10 2 μH = 3.3mH. The tolerance for F = 1%.