Resistor Color Code Calculator (4-Band)

Resistor Color Code Calculator (4-Band). Resistors — the small components that control electrical current — are marked with colored bands instead of printed numbers, and the Resistor Color Code Calculator (4-Band) decodes those bands into an actual resistance value. Select the colors for the 1st Band, 2nd Band, Multiplier, and Tolerance bands from your resistor to get the Resistance Value in ohms. Secondary outputs include the Tolerance percentage and the Minimum and Maximum acceptable resistance values. Also try the calculate Final Resistance, Resistance Change & Percentage Change — Temperature Coefficient of Resistance.

Resistor Color Code Calculator (4-Band) inputs

Results

Resistance Value

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Tolerance

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Minimum Value

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Maximum Value

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How to Calculate 4-Band Resistor Values?

Reading a 4-band resistor is straightforward: the first two bands represent significant digits, the third band is the multiplier, and the fourth band indicates tolerance. For example, Brown-Red-Red-Gold equals 12 × 100Ω = 1.2kΩ with ±5% tolerance. See also our Resistors in Parallel Calculator.

What is the difference between 4-band and 5-band resistors?

4-band resistors have two significant digits and are typically ±5% or ±10% tolerance, suitable for general applications. 5-band resistors have three significant digits offering higher precision with ±1% or ±2% tolerance for more critical circuits.

How do I read resistor colors if I'm colorblind?

Use a digital multimeter to measure the actual resistance value, or ask someone to help identify the colors. Some mobile apps can also identify resistor colors using your phone's camera to help with color recognition.

What does the tolerance band tell me?

The tolerance band indicates how much the actual resistance can vary from the nominal value. Gold means ±5%, silver means ±10%, and other colors indicate tighter tolerances like brown (±1%) or red (±2%).

Can I use this calculator for surface mount resistors?

No, this calculator is specifically for axial through-hole resistors with color bands. Surface mount resistors use numerical codes printed on them instead of color bands, requiring a different decoding method.

What happens if my resistor doesn't have exactly 4 bands?

This calculator is designed for 4-band resistors only. If your resistor has 3, 5, or 6 bands, you'll need a different calculator or reference chart as the color code interpretation varies with the number of bands.

Why is the first band never black in 4-band resistors?

The first band represents the first significant digit, and starting with zero would be meaningless (like writing 047 instead of 47). Therefore, 4-band resistors typically start with brown (1) through white (9) for the first band.

How accurate are the calculated minimum and maximum values?

The min/max values show the acceptable resistance range based on the tolerance band. For example, a 1kΩ resistor with ±5% tolerance will measure between 950Ω and 1050Ω when tested with a multimeter. You might also find our Resistor Color Code (5-Band) Calculator useful.