Resistor Color Code Calculator
Decode resistor color bands instantly. Supports 4-band, 5-band, 6-band through-hole resistors and SMD chip codes. Free online tool for electronics engineers.
103 = 10 × 10³ = 10kΩ
4-digit: 1002 = 100 × 10² = 10kΩ
EIA-96: 01C = 100 × 100 = 10kΩ
How to Read Resistor Color Codes
Resistor color codes are a standardized system for marking the value of through-hole resistors. Each colored band represents a digit, multiplier, or tolerance value. The first 2-3 bands are significant digits, followed by a multiplier band, and finally a tolerance band. A 6-band resistor adds a temperature coefficient band.
The color code formula is: Resistance = (Digit1 × 10 + Digit2 + Digit3...) × Multiplier
| Color | Digit | Multiplier | Tolerance |
|---|---|---|---|
| Black | 0 | ×1 (10⁰) | -- |
| Brown | 1 | ×10 (10¹) | ±1% |
| Red | 2 | ×100 (10²) | ±2% |
| Orange | 3 | ×1k (10³) | -- |
| Yellow | 4 | ×10k (10⁴) | -- |
| Green | 5 | ×100k (10⁵) | ±0.5% |
| Blue | 6 | ×1M (10⁶) | ±0.25% |
| Violet | 7 | ×10M (10⁷) | ±0.1% |
| Grey | 8 | ×100M (10⁸) | -- |
| White | 9 | ×1G (10⁹) | -- |
| Gold | -- | ×0.1 | ±5% |
| Silver | -- | ×0.01 | ±10% |
Common Use Cases
- Electronics Repair: Quickly identify burned or faded resistor values on PCB boards without a multimeter.
- Prototyping: Verify resistor values before soldering to ensure correct component selection for breadboard circuits.
- Education: Teach students the resistor color code system in electronics and electrical engineering courses.
- PCB Assembly: Quality assurance check during manual PCB population to confirm correct resistor placement.
- Inventory Management: Identify unmarked or mixed resistor batches in component storage bins.
Frequently Asked Questions
What's the difference between 4-band and 5-band resistors?
A 4-band resistor uses 2 significant digits (e.g., 47 = Yellow + Violet), a multiplier, and a tolerance band. A 5-band resistor uses 3 significant digits (e.g., 475 = Yellow + Violet + Green), offering more precise resistance values. 5-band resistors are commonly used for 1% tolerance or better applications.
What does a gold or silver band mean?
Gold and silver bands indicate tolerance when in the last position (±5% and ±10% respectively). If they appear in the third position (4-band) or fourth position (5-band), they act as a decimal multiplier: Gold = ×0.1, Silver = ×0.01. This allows sub-ohm values like 0.47Ω (Yellow-Violet-Silver).
How do I read a 6-band resistor?
A 6-band resistor is read the same as a 5-band resistor, with an additional sixth band indicating the temperature coefficient in ppm/°C. This tells you how much the resistance changes with temperature. Common values: Brown = 100 ppm, Red = 50 ppm, Orange = 15 ppm, Yellow = 25 ppm, Blue = 10 ppm, Violet = 5 ppm.
Which direction should I read the bands?
Hold the resistor so the tolerance band (usually gold, silver, or spaced farther apart) is on the right side. Read the bands from left to right. If there is no obvious tolerance band, try both directions — one will result in a standard E-series value, the other will not.