Resistor Color Code Calculator
Convert resistor color bands into accurate resistance values, tolerance, and power rating instantly. Perfect for electronics projects and circuit design
Calculator
Select the color bands of your resistor to calculate its resistance and tolerance.
About the Resistor Color Code Calculator
The Resistor Color Code Calculator is a free online tool that helps you decode resistor color bands and find their exact resistance value, tolerance, and multiplier in seconds. It supports 4-band, 5-band, and 6-band resistors, making it an useful tool for electronics students, engineers, and DIY circuit designers.
How the Calculator Works
Each color band on a resistor represents a number, multiplier, or tolerance. This calculator follows the standard IEC 60062 resistor color code to determine the value using:
- First Band: The first significant digit of resistance.
- Second Band: The second significant digit.
- Multiplier Band: Determines the power of ten by which the first two digits are multiplied.
- Tolerance Band: Indicates the precision range of the resistor value.
The basic formula used to calculate the resistance is:
R (Ω) = (First Digit × 10 + Second Digit) × Multiplier
For example, a resistor with color bands Red – Violet – Brown – Gold gives: (2×10 + 7) × 10¹ = 270 Ω ±5%.
Understanding Resistor Color Codes
The color bands correspond to numeric values standardized in electronics. Here’s a quick reference:
- Black: 0 Brown: 1 Red: 2 Orange: 3 Yellow: 4
- Green: 5 Blue: 6 Violet: 7 Gray: 8 White: 9
- Gold: Multiplier ×0.1 | Tolerance ±5%
- Silver: Multiplier ×0.01 | Tolerance ±10%
Higher precision resistors may also include a sixth temperature coefficient band (ppm/°C) for advanced designs or instrumentation circuits.
Why Use the Resistor Color Code Calculator
- Instant results: Quickly identify resistance values without manual decoding.
- Error-free design: Avoid mistakes in component selection during circuit prototyping.
- Educational aid: Ideal for learning resistor color coding in electrical and electronics courses.
- Mobile-friendly interface: Works on smartphones, tablets, and desktops for on-the-go use.
Whether you’re working on Arduino projects, PCB design, or electronic repair, this calculator saves time and ensures accurate resistor identification.
Applications
Understanding resistor color codes is vital for:
- Circuit design and prototyping — selecting correct resistor values for voltage dividers, biasing, and filters.
- Repair and troubleshooting — identifying unknown resistors in existing circuits.
- Electronics education — teaching the fundamentals of resistance, tolerance, and precision components.