Resistor Color Code

How it works

Decode the resistance value and tolerance of axial resistors using the standard electronic color code system.

Determine resistance and tolerance from color band codes

Description

The Resistor Calculator is a precision utility for electronics engineers, students, and hobbyists. Most through-hole resistors use a series of colored bands to indicate their value because they are too small for printed text. This tool allows you to select the color for each band (Brown, Black, Red, etc.) for both 4-band (standard) and 5-band (precision) resistors to instantly find the resistance value in Ohms and the manufacturing tolerance percentage.

Inputs

• Band Count: Choose between 4-band or 5-band configuration.
• Bands 1-3/4: Select the colors corresponding to the digits and multiplier.
• Tolerance Band: Select the final band color (typically Gold, Silver, or Brown).

Outputs

• Resistance: The total value (automatically formatted to $k\Omega$ or $M\Omega$ for large values).
• Tolerance: The $\pm%$ precision of the component.

Chart

• N/A: This tool provides direct numeric electrical results.

“Good to Know”

• The Multiplier: The third band (on 4-band) or fourth band (on 5-band) is the “multiplier.” It represents the number of zeros added to the digits.
• Standard Colors:
  • Black: 0
  • Brown: 1
  • Red: 2
  • Gold Multiplier: x0.1
  • Silver Multiplier: x0.01
• Reading Direction: Resistors are read toward the “tolerance” band. The tolerance band is usually spaced slightly further apart from the others or is a distinct color like Gold or Silver.

Examples

Example 1: Standard 1kΩ Resistor

• Input: 4-Band: Brown, Black, Red, Gold
• Output: 1 kΩ ±5%

Example 2: Precision 10kΩ

• Input: 5-Band: Brown, Black, Black, Red, Brown
• Output: 10 kΩ ±1%

Example 3: Low Resistance

• Input: 4-Band: Red, Red, Gold, Gold
• Output: 2.2 Ω ±5%