Engineering Reference
SMD Resistor Marking Code Reference
Lookup 3-digit, 4-digit, R-decimal, zero-ohm, and EIA-96 SMD resistor markings, multiplier letters, examples, and interpretation limits.
- Reading Time
- 13 min
- EIA-96 Values
- 96
- Updated
- September 27, 2026
Marking System Lookup
| System | Pattern | Decode rule | Example |
|---|---|---|---|
| 3-digit | XXN | XX × 10ᴺ Ω | 472 = 4.7 kΩ |
| 4-digit | XXXN | XXX × 10ᴺ Ω | 1001 = 1 kΩ |
| R notation | digits with R | R is decimal point in ohms | 4R7 = 4.7 Ω |
| Leading R | RXX | 0.XX Ω | R22 = 0.22 Ω |
| Zero-ohm | 000 or 0000 | Jumper nominally near 0 Ω | Check current rating |
| EIA-96 | NNL | Index NN × letter multiplier | 01C = 10 kΩ |
EIA-96 Base-Value Index
These values come directly from the shared decoder table used by the SMD calculator.
| 01-24 | 25-48 | 49-72 | 73-96 |
|---|---|---|---|
| 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 |
EIA-96 Multiplier Letters
| Letter | Multiplier | Interpretation |
|---|---|---|
| Z | ×0.001 | Low-ohm scaling |
| Y | ×0.01 | Low-ohm scaling |
| R | ×0.01 | Low-ohm scaling |
| X | ×0.1 | Low-ohm scaling |
| S | ×0.1 | Low-ohm scaling |
| A | ×1 | Base value in ohms |
| B | ×10 | Higher-decade scaling |
| H | ×10 | Higher-decade scaling |
| C | ×100 | Higher-decade scaling |
| D | ×1000 | Higher-decade scaling |
| E | ×10000 | Higher-decade scaling |
| F | ×100000 | Higher-decade scaling |
Worked Lookup Examples
| Code | Method | Result |
|---|---|---|
| 103 | 10 × 10³ Ω | 10 kΩ |
| 472 | 47 × 10² Ω | 4.7 kΩ |
| 1001 | 100 × 10¹ Ω | 1 kΩ |
| 4992 | 499 × 10² Ω | 49.9 kΩ |
| 4R7 | Replace R with decimal point | 4.7 Ω |
| R22 | Leading decimal marker | 0.22 Ω |
| 01C | Index 01 = 100; C = ×100 | 10 kΩ |
| 68X | Index 68 = 499; X = ×0.1 | 49.9 Ω |
Common Marking Mistakes
- Reading the final digit as an ordinary digit instead of an exponent.
- Using a 3-digit rule on a 4-digit precision code.
- Treating R as a unit suffix rather than a decimal point.
- Reading EIA-96 digits as a direct resistance value.
- Ignoring multiplier-letter aliases used by the shared lookup.
- Assuming every three-character code is EIA-96.
- Assuming an unmarked package is a zero-ohm jumper.
- Inferring tolerance solely from the top marking.
- Ignoring proprietary manufacturer codes.
- Measuring in circuit without accounting for parallel paths.
- Confusing resistor and inductor markings.
- Using a decoded nominal value without checking power, voltage, pulse, and temperature ratings.
Support reference
FAQ
How do I read a 3-digit SMD resistor code?
The first two digits are significant and the third is the decimal power-of-ten multiplier. For example, 472 is 47 × 10² = 4.7 kΩ.
How do I read a 4-digit SMD resistor code?
The first three digits are significant and the fourth is the multiplier exponent. For example, 1001 is 100 × 10¹ = 1 kΩ.
What does R mean in an SMD resistor marking?
R marks the decimal point in an ohmic value, so 4R7 means 4.7 Ω and R22 means 0.22 Ω.
What does 000 mean on a resistor?
000 commonly identifies a zero-ohm jumper, but manufacturer documentation should confirm the marking and current rating.
What is an EIA-96 resistor code?
It uses a two-digit index selecting one of 96 base values and a letter selecting a multiplier.
Does the EIA-96 letter always mean the same multiplier?
The standard lookup used here includes accepted aliases such as Y/R, X/S, and B/H. Verify unusual manufacturer markings.
Does an SMD marking show tolerance?
Not reliably for every system. EIA-96 is commonly associated with precision parts, but exact tolerance comes from the part specification.
Why are some SMD resistors unmarked?
Small packages, low-value parts, production choices, and manufacturer coding practices can leave components unmarked.
Can I decode every manufacturer code with these tables?
No. Fusible, current-sense, network, military, and proprietary markings may use different systems.
What does 01C mean?
Index 01 selects base 100 and C multiplies by 100, giving 10,000 Ω or 10 kΩ.
Is 100 the same in 3-digit and EIA-96 notation?
No. Numeric 100 is a 3-digit code for 10 Ω; an EIA-96 marking requires two digits plus a letter.
Should I measure an unknown resistor?
Yes when identification is uncertain, preferably isolated from parallel circuit paths and after confirming the circuit is de-energized.
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