SMD (Surface-Mount Device) resistors use a 3-digit or 4-digit code on their surface to show resistance. This calculator helps you find the resistance from these codes or get the correct code from a resistance value.
Use the tabs below to switch between decoding and encoding. Whether you are fixing a PCB, building a project, or checking a parts list, this tool helps you understand SMD resistor codes fast.
Code | Resistance |
---|---|
100 | 10 Ω |
472 | 4.7 kΩ |
103 | 10 kΩ |
1001 | 10 kΩ |
104 | 100 kΩ |
105 | 1 MΩ |
Why do some resistors have more than one code? The code "103" (3-digit) and "1001" (4-digit) both mean 10 kΩ. They are different because of how exact they are. 4-digit codes are for 1% tolerance resistors. 3-digit codes are usually for 5% tolerance resistors.
How to read the codes: For a 3-digit code, the first two digits are the main number. The third digit tells how many zeros to add. For example, "472" means 47 plus two zeros = 4700 Ω or 4.7 kΩ. A 4-digit code like "1001" means 100 × 10^1 = 1000 Ω or 1 kΩ.
This page is part of our Electronics Tools. You can also try our color ring resistor calculator or LED Resistor Calculator.
SMD (Surface-Mount Device) resistors are tiny components mounted directly onto the surface of a printed circuit board (PCB).
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