Resistor Color Code Calculator
What is Resistor Color Coding?
Resistor color codes are an international standard for indicating electronic component values through colored bands. Most resistors use 4 or 5 colored bands to specify their resistance value in ohms (Ω), tolerance (precision), and sometimes temperature coefficient.
Resistor Color Code Formula
The resistance value is calculated using:
For 4-band resistors:
(1st Digit × 10 + 2nd Digit) × Multiplier ± Tolerance
For 5-band resistors:
(1st Digit × 100 + 2nd Digit × 10 + 3rd Digit) × Multiplier ± Tolerance
| Color | Digit | Multiplier | Tolerance |
|---|---|---|---|
| Black | 0 | x1Ω | – |
| Brown | 1 | x10Ω | ±1% |
| Red | 2 | x100Ω | ±2% |
| Orange | 3 | x1kΩ | – |
| Yellow | 4 | x10kΩ | – |
| Green | 5 | x100kΩ | ±0.5% |
| Blue | 6 | x1MΩ | ±0.25% |
| Violet | 7 | x10MΩ | ±0.1% |
| Gray | 8 | x100MΩ | ±0.05% |
| White | 9 | x1GΩ | – |
| Gold | – | x0.1Ω | ±5% |
| Silver | – | x0.01Ω | ±10% |
How to Use This Calculator
- Select 4 or 5 bands using the dropdown
- Choose colors for each band using the color-coded selectors
- Click Calculate to see resistance value and tolerance range
- Read the chart showing minimum/maximum values
Key Factors Affecting Resistance Values
- Band color interpretation accuracy
- Resistor manufacturing tolerances
- Temperature coefficients
- Power rating limitations
- Measurement equipment precision
- Component aging effects
FAQ
Which end of the resistor do I start reading from?
Look for the tolerance band (usually gold or silver) – this is always the last band.
What if my resistor has 6 bands?
The 6th band typically indicates temperature coefficient – use our 5-band calculator and ignore the last band.
How accurate are color code readings?
Typical tolerance ranges from ±0.05% to ±10% depending on the tolerance band color.