This SMD resistor code calculator finds the resistance value. It uses the code printed on the resistor. It supports three code formats: 3-digit, 4-digit, and EIA-96. In a 3-digit code (used on ±5% tolerance parts), the first two digits are the significant digits, and the third is the multiplier.
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In a 4-digit code (used on ±1% parts), the first three digits are significant and the last is the multiplier. R marks a decimal point in any code (for example, “3R3” means 3.3Ω).
EIA-96 codes for ±1% parts use two digits for a standard value from a lookup table. They also use a letter for the multiplier. A stands for 1, B for 10, C for 100, and so on.
- 3-digit code (±5%): Commonly used in cost-sensitive consumer PCB designs. Example: ‘472’ means 47×10² = 4700Ω (4.7 kΩ).
- 4-digit code (±1%): Ideal for precision industrial and automotive PCB applications. Example: ‘1002’ means 100×10² = 10000Ω (10 kΩ).
- EIA-96 code (±1%): Used in high-density, miniaturized PCB layouts for aerospace and medical devices. Example: ’38C’ means 243×100 = 24300Ω.
SMD Resistor Code Reference Table
| Code | Resistance | Tolerance | Notes | PCB Application Example |
|---|---|---|---|---|
| 100 | 10 Ω | ±5% | 3-digit code | Used as current limiting resistors in LED PCB circuits |
| 472 | 4.7 kΩ | ±5% | 3-digit | Common in signal conditioning circuits for industrial PCBs |
| 103 | 10 kΩ | ±5% | 3-digit | Used in pull-up resistor configurations for microcontroller PCBs |
| 1001 | 10 kΩ | ±1% | 4-digit | Precision voltage dividers in automotive PCB designs |
| 104 | 100 kΩ | ±5% | 3-digit | Used in low-power sensor circuits for IoT PCBs |
| 105 | 1 MΩ | ±5% | 3-digit | High-impedance biasing in RF PCB layouts |
Usage
Select code format: Choose “3-digit”, “4-digit”, or “EIA-96” from the dropdown.
Enter the code: Type the marking on the resistor (use R for a decimal, if needed).
Calculate: Click the Calculate button.
Read result: The resistance (in Ω, kΩ, or MΩ) and the tolerance will display below the button.
Once you’ve calculated the resistance for your SMD resistor, use our PCB Trace Width Calculator to ensure your PCB traces can handle the current without overheating, or explore our PCB assembly services to bring your design to life.
