How do I read the code on an SMD resistor?
A chip resistor is too small for colour bands, so its value is printed as a short code on the black top. There are four ways to write it, and the number of characters tells you which one you have.
3-digit code: 472
Two digits for the value, then the number of zeros. 472 = 47 × 10² = 4,700 Ω = 4.7 kΩ.
Used on ±5% parts (E24 values). Below 10 Ω an R marks the decimal point: 4R7 = 4.7 Ω.
4-digit code: 4702
Three digits for the value, then the number of zeros. 4702 = 470 × 10² = 47,000 Ω = 47 kΩ.
Used on ±1% parts. Below 100 Ω an R marks the decimal point: 47R0 = 47 Ω.
EIA-96 code: 01C
Two digits are a place in the E96 table, the letter is the multiplier. 01C = 100 × 100 = 10 kΩ.
Used on small 1% parts, mostly 0603, where four digits do not fit. Only the 96 E96 values have a code.
R notation: R100
The R is the decimal point. R100 = 0.100 Ω, 4R7 = 4.7 Ω, 10R = 10 Ω.
Used for low values, often current-sense resistors. 000 or 0 is a zero-ohm jumper.
Which values can each system hold?
A 3-digit code holds two significant digits, so 4.99 kΩ cannot be written in it; the generator then shows the nearest E24 value, 5.1 kΩ (512), and says so. A 4-digit code holds three digits. EIA-96 holds only E96 values: 4.7 kΩ has no EIA-96 code, and the generator names the nearest one, 4.75 kΩ (66B).
Can I see a few worked out?
Each line is worked out by the same code as the generator above.
103 = 10 kΩ
10 × 10³ = 10,000 Ω = 10 kΩ
Picture of 103472 = 4.7 kΩ
47 × 10² = 4,700 Ω = 4.7 kΩ
Picture of 4724702 = 47 kΩ
470 × 10² = 47,000 Ω = 47 kΩ
Picture of 47021001 = 1 kΩ
100 × 10¹ = 1,000 Ω = 1 kΩ
Picture of 100101C = 10 kΩ
01 = 100 in the EIA-96 table, C = ×100, so 100 × 100 = 10 kΩ
Picture of 01C68B = 4.99 kΩ
68 = 499 in the EIA-96 table, B = ×10, so 499 × 10 = 4.99 kΩ
Picture of 68B4R7 = 4.7 Ω
R stands for the decimal point: 4R7 = 4.7 Ω
Picture of 4R7R100 = 0.1 Ω
R stands for the decimal point: R100 = 0.1 Ω
Picture of R100What code does a common value have?
The 24 values bought most often, from the zero-ohm jumper and the 0.1 Ω sense resistor to 1 MΩ, in all four systems. “None” means the value cannot be written in that system.
| Value | 3-digit | 4-digit | EIA-96 | R notation | Picture |
|---|---|---|---|---|---|
| 0 Ω (jumper) | 000 | 0000 | none | none | Make it |
| 0.1 Ω | R10 | R100 | 01Z | R10 | Make it |
| 1 Ω | 1R0 | 1R00 | 01Y | 1R0 | Make it |
| 4.7 Ω | 4R7 | 4R70 | none (nearest 66Y = 4.75 Ω) | 4R7 | Make it |
| 10 Ω | 100 | 10R0 | 01X | 10R | Make it |
| 22 Ω | 220 | 22R0 | none (nearest 34X = 22.1 Ω) | 22R | Make it |
| 47 Ω | 470 | 47R0 | none (nearest 66X = 47.5 Ω) | 47R | Make it |
| 100 Ω | 101 | 1000 | 01A | not used above 100 Ω | Make it |
| 220 Ω | 221 | 2200 | none (nearest 34A = 221 Ω) | not used above 100 Ω | Make it |
| 330 Ω | 331 | 3300 | none (nearest 51A = 332 Ω) | not used above 100 Ω | Make it |
| 470 Ω | 471 | 4700 | none (nearest 66A = 475 Ω) | not used above 100 Ω | Make it |
| 680 Ω | 681 | 6800 | none (nearest 81A = 681 Ω) | not used above 100 Ω | Make it |
| 1 kΩ | 102 | 1001 | 01B | not used above 100 Ω | Make it |
| 2.2 kΩ | 222 | 2201 | none (nearest 34B = 2.21 kΩ) | not used above 100 Ω | Make it |
| 3.3 kΩ | 332 | 3301 | none (nearest 51B = 3.32 kΩ) | not used above 100 Ω | Make it |
| 4.7 kΩ | 472 | 4701 | none (nearest 66B = 4.75 kΩ) | not used above 100 Ω | Make it |
| 5.1 kΩ | 512 | 5101 | none (nearest 69B = 5.11 kΩ) | not used above 100 Ω | Make it |
| 10 kΩ | 103 | 1002 | 01C | not used above 100 Ω | Make it |
| 22 kΩ | 223 | 2202 | none (nearest 34C = 22.1 kΩ) | not used above 100 Ω | Make it |
| 47 kΩ | 473 | 4702 | none (nearest 66C = 47.5 kΩ) | not used above 100 Ω | Make it |
| 100 kΩ | 104 | 1003 | 01D | not used above 100 Ω | Make it |
| 220 kΩ | 224 | 2203 | none (nearest 34D = 221 kΩ) | not used above 100 Ω | Make it |
| 470 kΩ | 474 | 4703 | none (nearest 66D = 475 kΩ) | not used above 100 Ω | Make it |
| 1 MΩ | 105 | 1004 | 01E | not used above 100 Ω | Make it |
How big is 0402, 0603, 0805, 1206 or 2512?
The name is the length and width in hundredths of an inch: 0603 is 0.06 × 0.03 inch, which is 1.6 × 0.8 mm (1608 in metric names). Sizes are nominal; each maker allows about ±0.1 to 0.2 mm.
| Size (inch name) | Metric name | Length × width | Typical power | Printed code |
|---|---|---|---|---|
| 0402 | 1005 | 1.0 × 0.5 mm | 1/16 W | Usually none |
| 0603 | 1608 | 1.6 × 0.8 mm | 1/10 W | Yes; 1% parts usually EIA-96 |
| 0805 | 2012 | 2.0 × 1.25 mm | 1/8 W | Yes |
| 1206 | 3216 | 3.2 × 1.6 mm | 1/4 W | Yes |
| 2512 | 6332 | 6.3 × 3.2 mm | 1 W | Yes |
Power ratings are typical for thick-film chip resistors at 70 °C; some series are rated higher. Check the datasheet of the exact part.
What value does each EIA-96 number stand for?
The two digits of an EIA-96 code are a place in this list of the 96 E96 values. The letter after them is the multiplier.
- 01100
- 02102
- 03105
- 04107
- 05110
- 06113
- 07115
- 08118
- 09121
- 10124
- 11127
- 12130
- 13133
- 14137
- 15140
- 16143
- 17147
- 18150
- 19154
- 20158
- 21162
- 22165
- 23169
- 24174
- 25178
- 26182
- 27187
- 28191
- 29196
- 30200
- 31205
- 32210
- 33215
- 34221
- 35226
- 36232
- 37237
- 38243
- 39249
- 40255
- 41261
- 42267
- 43274
- 44280
- 45287
- 46294
- 47301
- 48309
- 49316
- 50324
- 51332
- 52340
- 53348
- 54357
- 55365
- 56374
- 57383
- 58392
- 59402
- 60412
- 61422
- 62432
- 63442
- 64453
- 65464
- 66475
- 67487
- 68499
- 69511
- 70523
- 71536
- 72549
- 73562
- 74576
- 75590
- 76604
- 77619
- 78634
- 79649
- 80665
- 81681
- 82698
- 83715
- 84732
- 85750
- 86768
- 87787
- 88806
- 89825
- 90845
- 91866
- 92887
- 93909
- 94931
- 95953
- 96976
EIA-96 multiplier letters
- Z×0.001
- Y/R×0.01
- X/S×0.1
- A×1
- B/H×10
- C×100
- D×1000
- E×10000
- F×100000
Example: 68B is 499 × 10 = 4.99 kΩ, and 01Y is 100 × 0.01 = 1 Ω.
Short answers to common questions
How do I read an SMD resistor code?
Count the characters. Three digits: the first two are the value and the last is how many zeros follow, so 472 is 47 and two zeros, 4,700 Ω. Four digits: the first three are the value and the last is the zeros, so 4702 is 47,000 Ω. Two digits and a letter is EIA-96: look the number up in the table and multiply by the letter, so 01C is 100 × 100 = 10 kΩ. An R anywhere is the decimal point: 4R7 is 4.7 Ω.
What does 103 mean on an SMD resistor?
103 is 10 followed by three zeros: 10,000 Ω, which is 10 kΩ. It is a 3-digit code, so the part is usually a ±5% resistor. The 4-digit version of the same value is 1002, and the EIA-96 version is 01C.
What does 01C mean on a resistor?
01C is an EIA-96 code. 01 is the first value in the EIA-96 table, 100, and C means ×100, so the resistor is 10 kΩ. EIA-96 codes are used on small 1% resistors, mostly 0603, where four digits do not fit.
What does the R mean in 4R7 or R100?
R stands for the decimal point. 4R7 is 4.7 Ω, R47 is 0.47 Ω, R100 is 0.1 Ω and 47R0 is 47 Ω. It is used for values below 10 Ω on 3-digit parts and below 100 Ω on 4-digit parts, often on low-value current-sense resistors.
Why does my 0402 resistor have no code?
A 0402 resistor is 1.0 × 0.5 mm, too small to print a readable code, so most carry none at all. Read the value from the reel or bag label, or measure it with a multimeter. The generator shows an 0402 part with a blank body for that reason.
What does 000 or 0 mean on an SMD resistor?
000, 0000 or a single 0 marks a zero-ohm jumper: a link that joins two pads, not a resistance. It is used to bridge a track on a board or to choose an option at assembly.
Why is there no EIA-96 code for 4.7 kΩ?
EIA-96 only covers the 96 values of the E96 (1%) series, and 4.7 is an E24 value that is not one of them. The nearest E96 values are 4.64 kΩ (65B) and 4.75 kΩ (66B). A 4.7 kΩ part is printed 472 (3-digit) or 4701 (4-digit).
Can I use the pictures?
Yes. Download the PNG or SVG and use it in notes, lessons, documentation or a project write-up. Every picture carries the wirecora.com mark along the bottom so people can find the generator.
Where do the codes and sizes come from?
The 3-digit, 4-digit and R codes follow the marking rules of IEC 60062; the EIA-96 table is the E96 series of IEC 60063. Sizes are the standard chip sizes used by resistor makers. Values are worked out with exact decimal arithmetic, not estimates, and checked by an automatic test. The page shows no ads and sets no cookies.
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