Resistor Color Code
Free online resistor color code decoder. No sign-up, no installation. Runs entirely in your browser.
What is a Resistor Color Code?
A resistor color code is a standard system used to identify the resistance value and tolerance of resistors. Color bands printed on resistors correspond to numerical values and multipliers. The most common types are 4-band resistors (with tolerance band) and 5-band resistors (with tolerance band, offering better accuracy).
Each color represents a digit (0-9) or a multiplier (×10, ×100, etc.). The first band(s) form the base value, the multiplier band scales it, and the tolerance band indicates accuracy. Gold and silver multipliers are used for fractional values like 0.1 and 0.01.
How to Use This Tool
Choose your resistor type (4-band or 5-band), select the color of each band from the dropdowns, and click Calculate to see the resistance value in ohms (Ω), kilohms (kΩ), or megohms (MΩ). The tolerance percentage is also displayed.
Reverse lookup: Enter a resistance value (e.g., 4700, 4.7k, 1.5M) and select the band quantity to find the matching color codes.
SMD codes: SMD resistors use a 3-digit or 4-digit code instead of color bands. Enter the code to decode the value.
Common Use Cases
Electronics enthusiasts and students use this tool to identify resistors during breadboard experiments and circuit building. PCB designers and engineers reference color codes when selecting component values. Repair technicians decode resistor values during troubleshooting without needing a multimeter.
Frequently Asked Questions
What does tolerance mean?
Tolerance indicates how accurate the resistor value is. A ±5% tolerance resistor with a nominal value of 100Ω could actually be between 95Ω and 105Ω. Tighter tolerances (like ±0.1%) are more precise but more expensive.
Why do some resistors have 5 or 6 bands?
5-band resistors add a third significant digit for greater precision. 6-band resistors add a temperature coefficient band, indicating how the resistance changes with temperature—important for precision applications.
What's the difference between gold and silver multipliers?
Gold is a ×0.1 multiplier and silver is a ×0.01 multiplier. These are used for fractional resistor values. For example, a 47-gold means 4.7Ω, and a 47-silver means 0.47Ω.
What is an SMD resistor code?
SMD (Surface Mount Device) resistors are small and use a compact 3-digit or 4-digit code instead of color bands. The first two or three digits are the significant figures, and the last digit is the multiplier (power of 10).
Can I use this tool to verify my resistor?
Yes! Use the 4-Band or 5-Band tab to decode the colors on any resistor you have. You can also use a multimeter to measure the actual value and compare it to the color code to check tolerance.
How do I read a resistor color code from left to right?
Always read from the end closest to one of the color bands. The first band is the first digit, the second band is the second digit, the third band is the multiplier, and the last band is the tolerance. For 5-band resistors, add a third digit band before the multiplier.