Resistor Color Code Calculator
Decode resistor color bands to find resistance and tolerance.
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Request a ToolHow to Use the Resistor Color Code Calculator
Select 4-band or 5-band, then choose the color for each band. The calculator decodes the bands and shows the resistance value, tolerance percentage, and the expected range of resistance.
About Resistor Color Code
Resistor color codes are a standardized system for marking resistance values on through-hole resistors. Each colored band represents a digit, multiplier, or tolerance value. This system has been in use since the 1920s and remains the standard for axial-lead resistors. While surface-mount resistors use numeric codes, the color band system is still widely used in education and through-hole component identification.
Frequently Asked Questions
How do resistor color codes work?
Each band represents a digit or multiplier. For 4-band resistors: Band 1 and 2 are digits, Band 3 is the multiplier, Band 4 is tolerance. For 5-band: Bands 1-3 are digits, Band 4 is the multiplier, Band 5 is tolerance.
How do I identify the first band?
The first band is closest to one end of the resistor. The tolerance band (often gold or silver) is at the opposite end. If uncertain, the wider gap between bands is on the tolerance side.
What does tolerance mean?
Tolerance indicates how much the actual resistance may differ from the marked value. A 100 ohm resistor with 5% tolerance can range from 95 to 105 ohms.