Resistor Color Code Calculator

Overview

The Resistor Color Code Calculator is a handy tool designed to help you identify the resistance and tolerance values of 4-band and 5-band resistors. Resistors are fundamental components in electronics, and their values are typically indicated by colored bands printed on their body. This calculator decodes these colors into readable numerical values.

How to Use

Select Number of Bands: Choose whether you have a 4-band or 5-band resistor.
Select Colors:
- Band 1 & 2: Represent the first two significant digits of the resistance value.
- Band 3:
  - For 4-band resistors, this is the Multiplier.
  - For 5-band resistors, this is the Third Significant Digit.
- Band 4:
  - For 4-band resistors, this is the Tolerance.
  - For 5-band resistors, this is the Multiplier.
- Band 5 (5-band only): Represents the Tolerance.
Read the Result: The calculator instantly displays the resistance value (in Ohms, kΩ, or MΩ), the tolerance percentage, and the range of possible resistance values based on that tolerance.

Understanding Resistor Color Codes

Resistor color codes are an international standard (IEC 60062) used to mark the value of resistors. Because resistors are small, printing numbers on them is difficult to read. Color bands provide a durable and easy-to-read way to indicate value.

The Color Code Chart

Each color corresponds to a number:

Black: 0
Brown: 1
Red: 2
Orange: 3
Yellow: 4
Green: 5
Blue: 6
Violet: 7
Grey: 8
White: 9

4-Band Resistors

The 4-band code is the most common variation.

Band 1: 1st Digit
Band 2: 2nd Digit
Band 3: Multiplier (Power of 10)
Band 4: Tolerance

Formula:

R = (D i g i t_{1} \times 10 + D i g i t_{2}) \times M u lt i pl i er

5-Band Resistors

5-band resistors are used for higher precision (lower tolerance) resistors.

Band 1: 1st Digit
Band 2: 2nd Digit
Band 3: 3rd Digit
Band 4: Multiplier
Band 5: Tolerance

Formula:

R = (D i g i t_{1} \times 100 + D i g i t_{2} \times 10 + D i g i t_{3}) \times M u lt i pl i er

Real-World Examples

Example 1: 4-Band Resistor

Colors: Red, Violet, Orange, Gold

Red (Band 1) = 2
Violet (Band 2) = 7
Orange (Multiplier) = x1,000 (1k)
Gold (Tolerance) = ±5%

Calculation:

27 \times 1, 000 = 27, 000Ω = 27 k Ω

Result: 27 kΩ ±5%

Example 2: 5-Band Resistor

Colors: Green, Blue, Black, Red, Brown

Green (Band 1) = 5
Blue (Band 2) = 6
Black (Band 3) = 0
Red (Multiplier) = x100
Brown (Tolerance) = ±1%

Calculation:

560 \times 100 = 56, 000Ω = 56 k Ω

Result: 56 kΩ ±1%

FAQ

What if my resistor has no 4th band?

If a resistor has only 3 bands, it is a 4-band resistor where the tolerance band is missing. This implies a default tolerance of ±20%.

Why are there 5-band resistors?

5-band resistors allow for an extra significant digit, providing more precision. They are typically used in precision circuits where exact resistance values are critical.

What do Gold and Silver bands mean?

Gold and Silver are primarily used for:

Tolerance: Gold = ±5%, Silver = ±10%.
Multiplier: Gold = x0.1, Silver = x0.01 (for very low resistance values).