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 0 0 0 1    
Brown 1 1 1 10  1% M = 1.0%
Red 2 2 2 100  2% P = 0.1%
Orange 3 3 3 1000 (=1k)   R = 0.01%
Yellow 4 4 4 10k   S = 0.001%
Green 5 5 5 100k    
Blue 6 6 6 1000k    
Violet 7 7 7      
Gray 8 8 8      
White 9 9 9      

3-Band Example

4-Band Example
6 - 2 - 3 - Silver
62 * 103
W, 10%
62 * 1000
W, 10%
62 kW, 10%


 

1 - 9 - 6 - 0 - Red
196 * 100
W, 0.1% Failure Rate
196 * 1
W, 0.1% Failure Rate
196
W, 0.1% Failure Rate


 

 

Numerical Value Coding

4 - 4 - 2 - 2
442 * 102
W
442 * 100
W
44 200
W
44.2 k
W
 

3-Digit Symbol Coding

 (1%)

A = 100, B = 101, C = 102, D = 103, E = 104, R = 10-1, S = 10-2

Example: 

  1.00 W,    01S
  12.1
W,    09R
  165
W,     22A
  4.32 M
W,  62E
Symbol W
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 W
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 W
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 W
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 W
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 W
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 W,  S01
  5%,    1.00
W,  S25
  10%,  1.00
W,  S49
  5%,    510
W,   A42
  10%,  820 k
W,  D60
2%
Symbol W
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 W
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 W
49 100
50 120
51 150
52 180
53 220
54 270
55 330
56 390
57 470
58 560
59 680
60 820