Ever picked up a resistor and wondered what those colored stripes mean? They're actually a code that tells you the resistor's value. Let's learn how to crack this code.

What Are Resistor Color Codes?

Resistors are small electronic components that restrict electrical flow. Instead of printing tiny numbers on them, manufacturers use colored bands as a code. Most resistors have 4 or 5 colored stripes.

The Basic Color Chart

Each color represents a number:

  • Black = 0
  • Brown = 1
  • Red = 2
  • Orange = 3
  • Yellow = 4
  • Green = 5
  • Blue = 6
  • Violet = 7
  • Gray = 8
  • White = 9

Memory trick: "Big Brown Rabbits Often Yield Great Big Vegetable Gardens Weekly"

Reading a 4-Band Resistor

Hold the resistor so the bands are on the left side. Read from left to right:

Band 1: First digit Band 2: Second digit Band 3: Multiplier (number of zeros to add) Band 4: Tolerance (how accurate it is)

Example

Let's say you have: Brown, Black, Red, Gold

  1. Brown = 1 (first digit)
  2. Black = 0 (second digit)
  3. Red = 2 (add two zeros)
  4. Gold = ±5% tolerance

Result: 10 + 00 = 1,000 ohms (or 1kΩ), ±5%

The Multiplier Band

The third band tells you how many zeros to add:

  • Black = ×1 (no zeros)
  • Brown = ×10 (one zero)
  • Red = ×100 (two zeros)
  • Orange = ×1,000 (three zeros)
  • Yellow = ×10,000 (four zeros)
  • Green = ×100,000 (five zeros)
  • Blue = ×1,000,000 (six zeros)

Special cases:

  • Gold = ×0.1 (divide by 10)
  • Silver = ×0.01 (divide by 100)

The Tolerance Band

The last band (usually gold or silver) shows how accurate the resistor is:

  • Gold = ±5%
  • Silver = ±10%
  • Brown = ±1%
  • Red = ±2%
  • No band = ±20%

More Examples to Practice

Yellow, Violet, Brown, Gold

  • 4, 7, add one zero = 470 ohms, ±5%

Brown, Black, Orange, Gold

  • 1, 0, add three zeros = 10,000 ohms (10kΩ), ±5%

Red, Red, Red, Gold

  • 2, 2, add two zeros = 2,200 ohms (2.2kΩ), ±5%

Quick Tips

  1. Turn it around: If you're not sure which end to start from, the tolerance band (gold or silver) is usually on the right
  2. Sometimes there's a gap: The tolerance band is often slightly separated from the others
  3. Use a chart: Keep a color code reference handy until you memorize it
  4. When in doubt, measure: Use a multimeter to double-check the resistance

5-Band Resistors

More precise resistors have 5 bands. They work the same way, but with three digits instead of two:

  • Band 1: First digit
  • Band 2: Second digit
  • Band 3: Third digit
  • Band 4: Multiplier
  • Band 5: Tolerance

Once you understand 4-band resistors, 5-band ones are easy—just add one more digit at the start.

With a little practice, reading resistor codes becomes second nature. Keep the color chart handy, and soon you'll be reading them like a pro!