SMD Resistor Codes: How to Find the Value of SMD Resistors

Electrical Technology

How to Calculate & Find the Value of SMD & EIA-96 SMD Resistor Resistors?

Table of Contents

SMD Resistor: Surface Mount Technology

SMD Resistor stands for “Surface Mount device” (Taken out from SMT = Surface Mount Technology) Resistor. These tiny chips are marked with three (3) or four (4) digit codes which are called SMD Resistor codes to indicate their resistance values.

Below are some given roles which help to know the exact value of an SMD resistor by seeing the printed character codes on those tiny chips.

The first two (2) digits or numbers will indicate the significant digits or numbers.
The third one will be multiplier (in Power of Ten i.e. 10^ something) and then must be multiply by the first Two (2) significant digits or number or the third one will indicate that how many Zeros should be added to the first Two (2) significant digits or number.
The letter “R” is used for Decimal Point “.” i.e. 1.1 Ω = 1R1 Ω
Resistances below 10 ohms (Ω) do not have a multiplier.

Examples of 3-Digit SMD Resistor Codes

250 = 25 x 10⁰= 25 x 1 = 25 Ω (This is only and only 25Ω not 250 Ω)

100 = 10 x 10⁰ = 10 x 1 = 10 Ω

721 = 72 x 10¹= 72 x 10 = 720 Ω

102 = 10 × 10² =10 x 100 = 1000Ω or 1kΩ 915 = 91 x 10⁵ = 91 x 100000 = 9,100,000 Ω = 9.1MΩ

4R7 = 4.7Ω

R12 = 0.12 Ω

Reading 4-Digit SMD Resistor Codes

There is nothing new but the same method to read the value of SMD resistors as mentioned above for the 3 digits SMD roosters. The only difference is that with the significant numbers. In short, in the above method, the first two digits indicate significant numbers while in this method, the first three digits or numbers will show the significant numbers. Lets see how to do it.

The first three (3) digits or numbers will indicate the significant digits or numbers.
The fourth one will be multiplier (in Power of Ten i.e. 10^ something) and then must be multiply by the first two (3) significant digits or number or the fourth one will indicate that how many Zeros should be add to the first Two (2) significant digits or number.
The letter “R” is used for Decimal Point “.” i.e. 11.5 Ω = 11R5 Ω (4-digit SMD resistors (E96 series).
Resistances below 10 ohms (Ω) do not have a multiplier.

Also read: Resistor & Types of Resistors

Examples of 4-Digit SMD Resistor Codes

2500 = 250 x 10⁰= 250 x 1 = 250 Ω (This is only and only 250Ω not 2500 Ω)

1000 = 100 x 10⁰ = 100x 1 = 100 Ω

7201 = 720 x 10¹= 720 x 10 = 7200 Ω or 7.2kΩ

1001 = 100 × 10¹ =100 x 10 = 1000 Ω or 1kΩ

1004 = 100 × 10⁴ =100 x 10000 = 1000,000 Ω or 1MΩ

R102 = 0.102 Ω (4-digit SMD resistors (E96 series)

0R10 = 0.1 x 10⁰= 0.1 x 1 = 0.1 Ω (4-digit SMD resistors (E24 series)

25R5 = 25.5Ω (4-digit SMD resistors (E96 series))

Reading EIA-96 SMD Resistor Codes

EIA-96 SMD Resistor Codes marking method is a new method which appeared on 1% of all SMD resistors. It consists of 3- Character codes.

Below are the rules to follow to know the value of EIA-96 SMD resistors.

The first two (2) digits or numbers will indicate the significant digits or numbers
The third one “Letter” is a multiplier (in Power of Ten i.e. 10^ something) and then must be multiplied by the first Two (2) significant digits.
Must follow the codes in Table (1) and (2).

Below is the table (1) to show the multiplier values of different Letters using the EIA-96 coding system for SMD Resistor Codes.

Table (1)

Letters	Multipliers
Z	0.001
R or Y	0.01
S or X	0.1
A	1
B or H	10
C	100
D	1000
E	10000
F	100000

Also, look in the examples of reading EIA-96 SMD Resistor Codes for importance the use of table (2)

Table (2)

Code	Value	Code	Value	Code	Value	Code	Value
01	100	25	178	49	316	73	562
02	102	26	182	50	324	74	576
03	105	27	187	51	332	75	590
04	107	28	191	52	340	76	604
05	110	29	196	53	348	77	619
06	113	30	200	54	357	78	634
07	115	31	205	55	365	79	649
08	118	32	210	56	374	80	665
09	121	33	215	57	383	81	681
10	124	34	221	58	392	82	698
11	127	35	226	59	402	83	715
12	130	36	232	60	412	84	732
13	133	37	237	61	422	85	750
14	137	38	243	62	432	86	768
15	140	39	249	63	442	87	787
16	143	40	255	64	453	88	806
17	147	41	261	65	464	89	825
18	150	42	267	66	475	90	845
19	154	43	274	67	487	91	866
20	158	44	280	68	499	92	887
21	162	45	287	69	511	93	909
22	165	46	294	70	523	94	931
23	169	47	301	71	536	95	953
24	174	48	309	72	549	96	976

Examples of EIA-96 SMD Resistor Codes

01F = 10M
01E = 1MΩ
01C= 10kΩ
01B = 1kΩ
01A = 100Ω
01X = 10Ω
01Y = 1Ω
66X = 475 x 0.1 = 47.5 …→ (in table (2), 66 = 475 and in table (1), X = 0.1. so 475 x 0.1 = 47.1Ω)
85Z = 750 x 0.001 = 0.75Ω → (in table (2), 85 = 750 and in table (1), Z = 0.001. so 750 x 0.001 = 0.75Ω)
36H = 232 x10 = 2320Ω = 2.32kΩ → (in table (2), 36 = 232 and in table (1), H = 10. so 232 x 10= 2.32kΩ)