Resistor Decoder
Precision Component Simulator
How to Use This Calculator
1
Select Color Bands
Choose the colors of each band on the resistor, from left to right. Most resistors have 4 or 5 bands.
2
Read the Resistance
The calculator converts the color combination into a resistance value in ohms, kilohms, or megohms.
3
Check the Tolerance
The last band indicates tolerance — gold is ±5%, silver is ±10%, and brown is ±1% for precision resistors.
Key Terms
- Significant Digits
- The first two (or three) color bands that encode the base numeric value of the resistor.
- Multiplier Band
- The band that indicates the power of ten by which to multiply the significant digits. Red = ×100, orange = ×1,000, etc.
- Tolerance Band
- The final band showing the guaranteed accuracy of the stated value. Gold (±5%) means a 100-ohm resistor could be 95-105 ohms.
- Temperature Coefficient
- An optional sixth band on precision resistors indicating how resistance changes with temperature, measured in ppm/°C.
- E-Series
- Standardized sets of preferred resistor values. E12 has 12 values per decade, E24 has 24, and E96 has 96 for high-precision work.
Real-World Examples
Example 1
Brown-Black-Red-Gold
Band 1: Brown (1), Band 2: Black (0), Band 3: Red (×100), Band 4: Gold (±5%)
Result: 1,000 ohms (1K) with ±5% tolerance. Actual value ranges from 950 to 1,050 ohms.
Example 2
Yellow-Violet-Orange-Silver
Band 1: Yellow (4), Band 2: Violet (7), Band 3: Orange (×1,000), Band 4: Silver (±10%)
Result: 47,000 ohms (47K) with ±10% tolerance. This is one of the most common resistor values in electronics.
Resistor Color Code Chart
| Color | Digit Value | Multiplier | Tolerance |
|---|
| Black | 0 | ×1 | — |
| Brown | 1 | ×10 | ±1% |
| Red | 2 | ×100 | ±2% |
| Orange | 3 | ×1,000 | ±0.05% |
| Gold | — | ×0.1 | ±5% |
Reading Resistor Color Codes with Confidence
Why Color Codes Exist
Resistors are too small for printed numbers to be legible, especially when soldered onto a circuit board. The color band system, standardized by the IEC, allows technicians to identify values at a glance. Each color maps to a digit (0-9), and the system has remained unchanged for decades.
Tips for Identifying Band Order
The tolerance band (gold or silver) is always on the right end. The first significant digit band is slightly closer to one end of the resistor body. On 5-band resistors, the three digit bands are grouped together with a wider gap before the multiplier and tolerance bands.