Surface Mount Capacitors and their Markings

AaronRollens April 12, 2023, 9:00pm 1

Decoding Capacitor Part Markings

This guide will take the mystery out of identifying part markings on the various styles of surface mount chip style capacitors.

Surface Mount Chip Capacitors

These utilize methods to mark capacitors too small to have the information presented outright. Your capacitor will have markings two to four characters is length. That length and how they are arranged will play a part in decoding.

Three-Digit EIA

Standard-tolerance SMD capacitors use a 3-digit code to mark the capacitance value on the part. The first two numbers will indicate the significant digits, and the third will be the multiplier. ‘R’ is used to indicate the position of a decimal point.


10	Significant Digits
7	Multiplier

To get our value we multiply our significant digits against our multiplier. We simply add that number of zeros on to the end. This value is in picofarads. To change to to microfarads, simply move the decimal point to the left six spaces.

10 + 0,000,000 = 100,000,000pf
100,000,000 pf = 100µF

Four-Digit EIA

Similar to the three digit EIA, the four digit format uses the beginning values to indicate the significant digits, the last digit as the multiplier and a letter designating a tolerance. ‘R’ is used to indicate the position of a decimal point. The four digit format allows for higher precision.

Tolerance code

Code	Tolerance Value in %
B	0.1
C	0.25
D	0.5
F	1
G	2
J	5
K	10
M	20
Z	+80/-20

The Tolerance code D = 0.5%

Two-Digit EIA ( EIA-198)

Sometimes there is so little room on the part that even the standards are not practical. The EIA-198 system of part marking uses two characters (one number and one letter) in which the letter represents the value and number represents the multiplier. There are a couple of things to know.

*This system is case sensitive.
You will notice that by using some of the lower-case versions of letters they could eliminate many of the troublesome numbers such as I and O. They too easily get confused for 1 and 0.
The capacitance codes are not based upon the capacitance value like the others
The first digit is used for capacitance and correlate to the following tables.
Please be aware, While this system is still measured in picofarads, The multiplier code is one more than what we are used to in the other two methods.

Code	pF
A	1
B	1.1
C	1.2
D	1.3
E	1.5
F	1.6
G	1.8
H	2
J	2.2
K	2.4
a	2.6

Code	pF
L	2.7
M	3
N	3.3
b	3.5
P	3.6
Q	3.9
d	4
R	4.3
e	4.5
S	4.7
f	5

Code	pF
T	5.1
U	5.6
m	6
V	6.2
W	6.8
n	7
X	7.5
t	8
Y	8.2
y	9
Z	9.1

Multiplier Code	Value
0	1
1	10
2	100
3	1,000
4	10,000
5	100,000
6	1,000,000
7	10,000,000
8	100,000,000
9	0.1

Comparison

Three-Digit EIA	Four-Digit EIA	Two-Digit EIA ( EIA-198)

107	107D	A8
100µF	100µF	100µF
-	0.5%	-

Resources

If you would rather do some pointing and clicking to find your value I recommend you check out our SMD Capacitor Code Calculator.