Resistor Color Code Decoder

In electronics, through-hole resistors use small painted colored bands wrapped around their bodies to indicate their resistance value and tolerance. Because the component itself is often too small to print text on legibly, this universal color code standard was adopted.

4-Band vs 5-Band Resistors

Most standard carbon or metal film resistors use a 4-band code. Precision resistors, which require an extra digit to convey their exact value, use a 5-band code.

• 4-Band: Band 1 (Digit), Band 2 (Digit), Band 3 (Multiplier), Band 4 (Tolerance).
• 5-Band: Band 1 (Digit), Band 2 (Digit), Band 3 (Digit), Band 4 (Multiplier), Band 5 (Tolerance).

How the Math Works

To decode the value manually, write down the numbers associated with the first two (or three) bands. Then, multiply that raw number by the multiplier indicated by the next band.

For example, on a 4-band resistor: If Band 1 is Brown (1) and Band 2 is Black (0), you have "10". If Band 3 is Red (Multiplier x100), you calculate 10 × 100 to get a final value of 1,000 Ohms (or 1kΩ).

Understanding Tolerance

Manufacturing processes are not perfect. The final band indicates the tolerance—the guaranteed maximum percentage the actual resistance will deviate from the mathematical calculated value. A gold band (±5%) on a 100Ω resistor means the true resistance of the hardware will be somewhere between 95Ω and 105Ω.