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Resistor Color Code

Decode color bands to resistance value, or encode a resistance value to color bands. Supports 4-band and 5-band resistors.

Bands:

Color Code Reference Table

Color	Digit	Multiplier	Tolerance

About Resistor Color Code

Resistor Color Code is a free scientific calculation tool that helps students, researchers, and engineers decode color bands to resistance value, or encode a resistance value to color bands. supports 4-band and 5-band resistors. Instead of looking up formulas and calculating by hand, enter your values and get instant, accurate results with clear explanations of the underlying science.

How to Use

Enter your known values Fill in the input fields with the values you have. The tool will calculate the unknowns.

Select units if applicable Choose the correct units for your calculation to ensure accurate results.

Review the solution Check the calculated result along with any formulas, steps, or diagrams shown.

Explore different values Change inputs to see how different values affect the outcome. Great for building scientific intuition.

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Why Use Resistor Color Code?

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Verified Formulas Resistor Color Code implements standard scientific formulas from physics, chemistry, and mathematics textbooks. Results you can trust for homework, research, and engineering.

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Step-by-Step Solutions Where applicable, see not just the answer but the calculation steps. Perfect for learning and verifying your own work.

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Instant Computation Complex calculations that take minutes by hand are solved in milliseconds. Explore different scenarios and parameters quickly.

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Great for Students Whether you're in high school physics or graduate-level engineering, Resistor Color Code helps you check your work and build intuition for the underlying concepts.

Frequently Asked Questions

For a 4-band resistor: the first two bands are digits, the third band is the multiplier, and the fourth is tolerance. For example, Red-Red-Red-Gold = 2-2-×100-±5% = 2200Ω ±5%. Read left to right, starting from the band closest to one end.

Tolerance indicates how close the actual resistance is to the stated value. Gold = ±5%, Silver = ±10%, Brown = ±1%, Red = ±2%. A 1kΩ ±5% resistor could be anywhere between 950Ω and 1050Ω. Lower tolerance means higher precision, typically at higher cost.

4-band resistors use 2 significant digits + multiplier + tolerance, while 5-band resistors use 3 significant digits + multiplier + tolerance. 5-band resistors offer greater precision and are used in high-accuracy applications. They are common in precision resistors with 1% or 0.5% tolerance.