Resistor Color Code Guide
Through-hole resistors use colored bands instead of printed numbers to identify their resistance value. By understanding the resistor color code, you can determine a resistor's resistance, multiplier, tolerance and, for precision resistors, its temperature coefficient. Learning the resistor color code is an essential skill for electronics students, hobbyists and professional technicians.
Why Are Color Bands Used?
Most resistors are too small to print numbers clearly on their bodies. Instead, manufacturers use internationally standardized colored bands that can be read quickly and accurately.
The color code is recognized worldwide and allows resistors from different manufacturers to be identified consistently.
Standard Color Code Table
| Color | Digit | Multiplier | Tolerance | TCR (ppm/°C) |
|---|---|---|---|---|
| Black | 0 | ×1 | — | 250 |
| Brown | 1 | ×10 | ±1% | 100 |
| Red | 2 | ×100 | ±2% | 50 |
| Orange | 3 | ×1,000 | — | 15 |
| Yellow | 4 | ×10,000 | — | 25 |
| Green | 5 | ×100,000 | ±0.5% | 20 |
| Blue | 6 | ×1,000,000 | ±0.25% | 10 |
| Violet | 7 | ×10,000,000 | ±0.1% | 5 |
| Grey | 8 | ×100,000,000 | ±0.05% | 1 |
| White | 9 | ×1,000,000,000 | — | 0.5 |
| Gold | — | ×0.1 | ±5% | — |
| Silver | — | ×0.01 | ±10% | — |
| No Band | — | — | ±20% | — |
4-Band Resistors
| Band | Meaning |
|---|---|
| 1 | First significant digit |
| 2 | Second significant digit |
| 3 | Multiplier |
| 4 | Tolerance |
Brown Black Red Gold 1 0 ×100 ±5% = 1,000 Ω = 1 kΩ ±5%
5-Band Resistors
| Band | Meaning |
|---|---|
| 1 | First digit |
| 2 | Second digit |
| 3 | Third digit |
| 4 | Multiplier |
| 5 | Tolerance |
Brown Black Black Red Brown 100 × 100 = 10,000 Ω = 10 kΩ ±1%
6-Band Resistors
| Band | Meaning |
|---|---|
| 1 | First digit |
| 2 | Second digit |
| 3 | Third digit |
| 4 | Multiplier |
| 5 | Tolerance |
| 6 | Temperature Coefficient (TCR) |
The sixth band specifies how much the resistance changes with temperature, usually measured in ppm/°C.
Common Resistor Values
| Colors | Value |
|---|---|
| Brown • Black • Brown • Gold | 100 Ω ±5% |
| Red • Red • Brown • Gold | 220 Ω ±5% |
| Yellow • Violet • Brown • Gold | 470 Ω ±5% |
| Brown • Black • Orange • Gold | 10 kΩ ±5% |
| Yellow • Violet • Yellow • Gold | 470 kΩ ±5% |
| Brown • Black • Green • Gold | 1 MΩ ±5% |
Reading Tips
- Start reading from the end opposite the tolerance band.
- The tolerance band is usually separated slightly from the other bands.
- Gold and silver bands almost always appear last.
- If no tolerance band is present, the tolerance is usually ±20%.
- When in doubt, confirm the value using a digital multimeter.
Common Mistakes
| Mistake | How to Avoid It |
|---|---|
| Reading from the wrong end. | Locate the tolerance band first. |
| Confusing red and orange. | Use good lighting or magnification. |
| Ignoring the multiplier. | Always calculate the multiplier before writing the final value. |
| Ignoring tolerance. | Remember that the measured value may vary within the specified tolerance. |
Testing a Resistor
- Read the color bands.
- Calculate the expected resistance.
- Disconnect power from the circuit.
- Measure the resistor using a digital multimeter.
- Compare the measured value with the calculated value.
- Verify that it is within the specified tolerance.
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Key Points
- The resistor color code is an international standard.
- 4-band resistors are common in general-purpose electronics.
- 5-band resistors provide greater precision.
- 6-band resistors include a temperature coefficient (TCR).
- Learning the color code makes identifying resistor values fast and reliable.