SMD code decoder
Type the code printed on a surface-mount resistor or capacitor and choose the part type. The decoder understands 3-digit and 4-digit resistor codes (472, 1002), codes with R as the decimal point (4R7), the 1 % EIA-96 codes (01C, 68X) and 3-digit capacitor codes with an optional tolerance letter (104K).
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How to use it
- Choose Resistor or Capacitor.
- Type the code exactly as printed. Case does not matter, and the decoder works out which kind of code it is.
- Read the value, and for resistors which type of code it was. For capacitors the value is shown in pF, nF and µF.
Code types
| Type |
Example |
Meaning |
| 3 digits |
472 |
47 × 10² = 4.7 kΩ |
| 4 digits |
1002 |
100 × 10² = 10 kΩ |
| R notation |
4R7 |
4.7 Ω |
| EIA-96 |
01C |
100 × 100 = 10 kΩ |
| Capacitor |
104 |
10 × 10⁴ pF = 100 nF |
Worked example
A resistor marked 68X uses the EIA-96 table. 68 is the 68th value in the table, 499, and X means ×0.1, so the resistor is 49.9 Ω. A capacitor marked 224K is 22 × 10⁴ = 220,000 pF = 220 nF, with a tolerance of ±10 %.
Tips
- On a very small part there may not be enough room for a code. Measure it with a multimeter, out of circuit, if you are not sure.
- A capacitor code does not tell you the voltage rating, and ceramic parts are often not marked at all.
Frequently asked questions
How do 3-digit and 4-digit resistor codes work?
The last digit is the number of zeros and the digits before it are the value in ohms. 472 is 47 followed by two zeros, 4,700 Ω or 4.7 kΩ. 1002 is 100 followed by two zeros, 10,000 Ω or 10 kΩ. Four-digit codes are normally used on 1 % parts, three-digit ones on 5 %.
What does the letter R mean in a code like 4R7?
R stands for the decimal point, so 4R7 is 4.7 Ω and R100 is 0.1 Ω. The decoder also accepts K and M in the same place, so 4K7 is 4.7 kΩ. A code of 000 or 0 marks a zero-ohm link.
How do I read an EIA-96 code such as 01C?
The two digits point into a table of 96 values from 100 to 976 (01 is 100, 49 is 316, 96 is 976) and the letter is a multiplier. Z is ×0.001, Y ×0.01, X ×0.1, A ×1, B ×10, C ×100, D ×1,000, E ×10,000 and F ×100,000. So 01C is 100 × 100 = 10 kΩ and 68X is 499 × 0.1 = 49.9 Ω.
How are capacitor codes read?
A three-digit code is in picofarads: the first two digits followed by the number of zeros. 104 is 10 followed by four zeros, 100,000 pF, which is 100 nF or 0.1 µF. A multiplier digit of 8 means ×0.01 and 9 means ×0.1, so 689 is 6.8 pF.
What do the letters after a capacitor code mean?
They give the tolerance. B is ±0.1 pF, C ±0.25 pF, D ±0.5 pF, F ±1 %, G ±2 %, J ±5 %, K ±10 %, M ±20 % and Z is −20 % / +80 %. So 224K is 220 nF with ±10 %.