Resistor Markings

Three methods of resistor markings are predominant - color coding, numerical value coding and three-digit symbol coding. MIL-PRF-55342 assigns part numbers using alpha-numeric coding. Tolerance, temperature, package style and failure rate are integrated into some numbering schemes.

Color Coding
(3-Band and 4-Band Resistors)

Color

1st
Significant
Digit

2nd
Significant
Digit

3rd
Significant
Digit
(if used)

Multiplier

Tolerance

Failure Rate Level
(% per 1000 hours)

None

±20%

Silver

0.01

±10%

Gold

0.1

±5%

Black

Brown

±1%

M = 1.0%

Red

100

±2%

P = 0.1%

Orange

1000 (=1k)

R = 0.01%

Yellow

10k

S = 0.001%

Green

100k

Blue

1000k

Violet

Gray

White

3-Band Example	4-Band Example
6 - 2 - 3 - Silver 62 * 10³ Ω, 10% 62 * 1000 Ω, 10% 62 kΩ, 10%	1 - 9 - 6 - 0 - Red 196 * 10⁰ Ω, 0.1% Failure Rate 196 * 1 Ω, 0.1% Failure Rate 196 Ω, 0.1% Failure Rate

Numerical Value Coding

4 - 4 - 2 - 2
442 * 10² Ω
442 * 100 Ω
44 200 Ω
44.2 kΩ

3-Digit Symbol Coding

(1%)

A = 10⁰, B = 10¹, C = 10², D = 10³, E = 10⁴, R = 10^-1, S = 10^-2
Example:	1.00 Ω, 01S 12.1 Ω, 09R 165 Ω, 22A 4.32 MΩ, 62E

Symbol	Ω
01	100
02	102
03	105
04	107
05	110
06	113
07	115
08	118
09	121
10	124
11	127
12	130
13	133
14	137
15	140
16	143

Symbol	Ω
17	147
18	150
19	154
20	158
2	162
22	165
23	169
24	174
25	178
26	182
27	187
28	191
29	196
30	200
31	205
32	210

Symbol	Ω
33	215
34	221
35	226
36	232
37	237
38	243
39	249
40	255
41	261
42	267
43	274
44	280
45	287
46	294
47	301
48	309

Symbol	Ω
49	316
50	324
51	332
52	340
53	348
54	357
55	365
56	374
57	383
58	392
59	402
60	412
61	422
62	432
63	442
64	453

Symbol	Ω
65	464
66	475
67	487
68	499
69	511
70	523
71	536
72	549
73	562
74	576
75	590
76	604
77	619
78	634
79	649
80	665

Symbol	Ω
81	681
82	698
83	715
84	732
85	750
86	768
87	787
88	806
89	825
90	845
91	866
92	887
93	909
94	931
95	953
96	976

A = 10⁰, B = 10¹, C = 10², D = 10³, E = 10⁴, R = 10^-1, S = 10^-2
Example:	2%, 1.00 Ω, S01 5%, 1.00 Ω, S25 10%, 1.00 Ω, S49 5%, 510 Ω, A42 10%, 820 kΩ, D60

2%
Symbol	Ω
01	100
02	110
03	120
04	130
05	150
06	160
07	180
08	200
09	220
10	240
11	270
12	300
13	330
14	360
15	390
16	430
17	470
18	510
19	560
20	620
21	680
22	750
23	820
24	910

5%
Symbol	Ω
25	100
26	110
27	120
28	130
29	150
30	160
31	180
32	200
33	220
34	240
35	270
36	300
37	330
38	360
39	390
40	430
41	470
42	510
43	560
44	620
45	680
46	750
47	820
48	910

10%
Symbol	Ω
49	100
50	120
51	150
52	180
53	220
54	270
55	330
56	390
57	470
58	560
59	680
60	820

Webmaster: Kirt Blattenberger, BSEE, UVM 1989