Resistor Codes

Resistors are color-coded and have at least two value bands and a multiplier; other bands are optional. To distinguish left from right there often is a gap after the multiplier band 1.

Color Digit 1 Digit 2 Digit 3 2 Multiplier Tolerance
Black 0 0 0 ×100
Brown 1 1 1 ×101 ±1%
Red 2 2 2 ×102 ±2%
Orange 3 3 3 ×103
Yellow 4 4 4 ×104
Green 5 5 5 ×105 ±0.5%
Blue 6 6 6 ×106 ±0.25%
Violet 7 7 7 ×107 ±0.1%
Gray 8 8 8 ×108 ±0.05%
White 9 9 9 ×109
Gold ×10-1 ±5%
Silver ×10-2 ±10%
None ±20%

SM ResistorsSurface-mount resistors have a 3-digit or 4-digit code on them instead. The first two or three digits are the first digits of the answer. The last digit represents the multiplier. The answer is in Ohms. For example: 334 means 33×104 Ω = 330 KΩ. Note that 100, 220 and 470 are 10 Ω, 22 Ω and 47 Ω respectively. Sometimes simply the 2-digit codes 10, 22 and 47 (without any multiplier) are printed on the resistor instead to avoid confusion. Another way to avoid mistakes is to print 10R, 22R or 47R on them. Often the letters K and M are used as well, e.g. 473 = 47K = 47 KΩ and 105 = 1M = 1 MΩ. The letters R, K and M are also used instead of a comma, e.g. 2K2 = 2,2 KΩ and 0R56 or simply R56 is an 0.56 Ω resistor.

However, making matters confusing, there’s a new coding system for SM resistors using a 2-digit code in combination with a multiplier letter. To decipher these, you’ll need the lookup tables below.

  • with 1% type SM resistors the multiplier letters comes after the digits, e.g. 22A is a 165 Ω resistor, 68C is a 49900 Ω or 49.9 KΩ (49K9) one and 43E a 2740000 Ω or 2.74 MΩ (2M74) one
  • 2% and 5% type resistors use alternative lookup tables and—to distinguish from 1% type resistors—the multiplier letter goes first, e.g. C31 is 5%, 18000 Ω (18K), and D18 is 510000 Ω (510K) 2% tolerance
±1% SM resistors
Code Value Code Value Letter Multiplier
1 100 49 316 A ×100
2 102 50 324 B/H ×101
3 105 51 332 C ×102
4 107 52 340 D ×103
5 110 53 348 E ×104
6 113 54 357 F ×105
7 115 55 365 X/S ×10-1
8 118 56 374 Y/R ×10-2
9 121 57 383 Z ×10-3
10 124 58 392
11 127 59 402
12 130 60 412
13 133 61 422
14 137 62 432
15 140 63 442
16 143 64 453
17 147 65 464
18 150 66 475
19 154 67 487
20 158 68 499
21 162 69 511
22 165 70 523
23 169 71 536
24 174 72 549
25 178 73 562
26 182 74 576
27 187 75 590
28 191 76 604
29 196 77 619
30 200 78 634
31 205 79 649
32 210 80 665
33 215 81 681
34 221 82 698
35 226 83 715
36 232 84 732
37 237 85 750
38 243 86 768
39 249 87 787
40 255 88 806
41 261 89 825
42 267 90 845
43 274 91 866
44 280 92 887
45 287 93 909
46 294 94 931
47 301 95 953
48 309 96 976
±2% SM resistors
Letter Multiplier Code Value Code Value
A ×100 1 100 13 330
B/H ×101 2 110 14 360
C ×102 3 120 15 390
D ×103 4 130 16 430
E ×104 5 150 17 470
F ×105 6 160 18 510
X/S ×10-1 7 180 19 560
Y/R ×10-2 8 200 20 620
Z ×10-3 9 220 21 680
10 240 22 750
11 270 23 820
12 300 24 910
±5% SM resistors
Letter Multiplier Code Value Code Value
A ×100 25 100 37 330
B/H ×101 26 110 38 360
C ×102 27 120 39 390
D ×103 28 130 40 430
E ×104 29 150 41 470
F ×105 30 160 42 510
X/S ×10-1 31 180 43 560
Y/R ×10-2 32 200 44 620
Z ×10-3 33 220 45 680
34 240 46 750
35 270 47 820
36 300 48 910

Notes:

  1. This is not the case in the image of the 1 KΩ (±5%) resistor above
  2. 3rd digit only for 5-band resistors

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