RESISTOR MARKING CODES
Surface Mount Resistor Marking Decoder
Enter a resistor 3 or 4 character marking code below and press enter to get its value.
Note: To avoid ambiguity, the letter 'R' is treated as a placeholder for low ohmic values rather than a multiplier in the EIA system. For use as a multiplier, use the letter 'Y' instead of 'R'. See below for more details on the coding systems.
Standard Markings
Surface mount resistors are generally identified with a numerical 3 or 4 digit code to indicate their value. This follows the same pattern as the familiar colour coding scheme, with the first 2 or 3 digits representing the value in ohms and the last digit indicating the multiplier.
| 3 Digit Examples | 4 Digit Examples | |
|---|---|---|
| 470 = 47 ohms | 1000 = 100 ohms | |
| 561 = 560 ohms | 5362 = 53.6k ohms | |
| 223 = 22k ohms | 8663 = 866k ohms | |
| 1R2 = 1.2 ohms | 0R47 = 0.47 ohms | |
| 1M5 = 0.0015 ohms | 22M1 = 0.0221 ohms |
EIA Markings
The new EIA-96 system of marking is altogether more complicated and even has subtle differences depending on whether the resistor tolerance is 1% or not.
- For 1% parts, the first 2 characters are numbers indicating the resistance value as given by a lookup table. The last character is a letter identifying the multiplier.
- For 2, 5 and 10% parts, the multiplier letter comes first and the following 2 digits employ a different lookup table.
The system's main benefit is that it only requires 3 characters to represent any value and so fits more easily on to even the smallest components.
EIA-96 1% Lookup Table
The table below shows the resistance value lookup table based on the first 2 digits for 1% parts.
| 1% | |||||||
|---|---|---|---|---|---|---|---|
| Code | Value | Code | Value | Code | Value | ||
| 01 | 100 | 33 | 215 | 65 | 464 | ||
| 02 | 102 | 34 | 221 | 66 | 475 | ||
| 03 | 105 | 35 | 226 | 67 | 487 | ||
| 04 | 107 | 36 | 232 | 68 | 499 | ||
| 05 | 110 | 37 | 237 | 69 | 511 | ||
| 06 | 113 | 38 | 243 | 70 | 523 | ||
| 07 | 115 | 39 | 249 | 71 | 536 | ||
| 08 | 118 | 40 | 255 | 72 | 549 | ||
| 09 | 121 | 41 | 261 | 73 | 562 | ||
| 10 | 124 | 42 | 237 | 74 | 576 | ||
| 11 | 127 | 43 | 274 | 75 | 590 | ||
| 12 | 130 | 44 | 280 | 76 | 604 | ||
| 13 | 133 | 45 | 287 | 77 | 619 | ||
| 14 | 137 | 46 | 294 | 78 | 634 | ||
| 15 | 140 | 47 | 301 | 79 | 649 | ||
| 16 | 143 | 48 | 309 | 80 | 665 | ||
| 17 | 147 | 49 | 316 | 81 | 681 | ||
| 18 | 150 | 50 | 324 | 82 | 698 | ||
| 19 | 154 | 51 | 332 | 83 | 715 | ||
| 20 | 158 | 52 | 340 | 84 | 732 | ||
| 21 | 162 | 53 | 348 | 85 | 750 | ||
| 22 | 165 | 54 | 357 | 86 | 768 | ||
| 23 | 169 | 55 | 365 | 87 | 787 | ||
| 24 | 174 | 56 | 374 | 88 | 806 | ||
| 25 | 178 | 57 | 383 | 89 | 825 | ||
| 26 | 182 | 58 | 392 | 90 | 845 | ||
| 27 | 187 | 59 | 402 | 91 | 866 | ||
| 28 | 191 | 60 | 412 | 92 | 887 | ||
| 29 | 196 | 61 | 422 | 93 | 909 | ||
| 30 | 200 | 62 | 432 | 94 | 931 | ||
| 31 | 205 | 63 | 442 | 95 | 953 | ||
| 32 | 210 | 64 | 453 | 96 | 976 | ||
EIA-96 2%, 5% and 10% Lookup Table
The table below shows the resistance value lookup table based on the last 2 digits for 2, 5 and 10% parts. Strangely, the 2% values follow the E24 series values rather than the expected E48 range.
| 2% | 5% | 10% | |||||
|---|---|---|---|---|---|---|---|
| Code | Value | Code | Value | Code | Value | ||
| 01 | 100 | 25 | 100 | 49 | 100 | ||
| 02 | 110 | 26 | 110 | ||||
| 03 | 120 | 27 | 120 | 50 | 120 | ||
| 04 | 130 | 28 | 130 | ||||
| 05 | 150 | 29 | 150 | 51 | 150 | ||
| 06 | 160 | 30 | 160 | ||||
| 07 | 180 | 31 | 180 | 52 | 180 | ||
| 08 | 200 | 32 | 200 | ||||
| 09 | 220 | 33 | 220 | 53 | 220 | ||
| 10 | 240 | 34 | 240 | ||||
| 11 | 270 | 35 | 270 | 54 | 270 | ||
| 12 | 300 | 36 | 300 | ||||
| 13 | 330 | 37 | 330 | 55 | 330 | ||
| 14 | 360 | 38 | 360 | ||||
| 15 | 390 | 39 | 390 | 56 | 390 | ||
| 16 | 430 | 40 | 430 | ||||
| 17 | 470 | 41 | 470 | 57 | 470 | ||
| 18 | 510 | 42 | 510 | ||||
| 19 | 560 | 43 | 560 | 58 | 560 | ||
| 20 | 620 | 44 | 620 | ||||
| 21 | 680 | 45 | 680 | 59 | 680 | ||
| 22 | 750 | 46 | 750 | ||||
| 23 | 820 | 47 | 820 | 60 | 820 | ||
| 24 | 910 | 48 | 910 | ||||
EIA Multiplier Lookup Table
The table below shows the resistance multiplier lookup table based on the last letter for 1% parts and the first letter for 2, 5 and 10% parts.
| Letter | Multiplier | Letter | Multiplier | |
|---|---|---|---|---|
| A | 1 | X or S | 0.1 | |
| B | 10 | Y or R | 0.01 | |
| C | 100 | Z | 0.001 | |
| D | 1,000 | |||
| E | 10,000 | |||
| F | 100,000 |
Other Features
- A marking of 0, 00, 000 or 0000 is a a zero ohm link.
- A 3 digit code with a short bar below the marking denotes a precision (1% or less) resistor from the E24 series (122 = 1.2kΩ 1%). Some manufacturers underline all three digits which is easily confused with the code used on low value current sensing resistors as described below.
- Low value resistors can be marked with a long bar on top of the code (3M3 = 3.3mΩ, R027 = 27mΩ, etc.).
- Low value resistors can be marked with a long bar under the code (101 = 0.101Ω, 056 = 0.056Ω). The underline is used when the starting 'R' has to be omitted due to the limited space on the resistor's body. So, for example, R047 becomes 047 = 0.047Ω.
Examples
- B54 = 2.7k ohms 10% tolerance
- C15 = 39k ohms 2% tolerance
- 19D = 154k ohms 1% tolerance
- 22R = 1.65 ohms 1% tolerance (or 22 ohms!)
- 1M5 = 1.5M ohms