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Resistor Color Code Calculator

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Select the color bands on your resistor to find its resistance value and tolerance - works for both 4-band and 5-band resistors.

Resistor Color Code Calculator

Live
Resistance
1,000 Ω (1kΩ)
Tolerance
±5%
Range
950 - 1,050 Ω

How resistor color codes work

4-band: [Digit 1][Digit 2][Multiplier][Tolerance] 5-band: [Digit 1][Digit 2][Digit 3][Multiplier][Tolerance] Resistance = (significant digits) x Multiplier
Example

Brown-Black-Red-Gold (4-band): digits 1-0, multiplier x100 -> 1,000Ω (1kΩ), tolerance ±5%, so the actual value falls somewhere between 950Ω and 1,050Ω.

Step-by-step guide

  1. Count the bands on your resistor and select 4-band or 5-band.
  2. Read the colors in order, starting from the band closest to one end (the tolerance band, usually gold or silver, is typically set apart slightly and read last).
  3. Select each color to match your resistor, and read the calculated resistance and tolerance range.

Which end do I start reading from?

The tolerance band (usually gold or silver, occasionally another color) is typically spaced slightly farther from the last digit band than the other bands are from each other - that gap is your cue for which end to start reading from. Read from the opposite end, moving toward the tolerance band last.

Common mistakes

Reading the bands backward - always start from the end farthest from the tolerance band, not the tolerance band itself.
Confusing a 5-band resistor's extra digit band with the multiplier band - a 5-band resistor has three significant digits before the multiplier, not two.

Frequently asked questions

What's the difference between a 4-band and 5-band resistor?

A 5-band resistor has an extra significant digit, giving it more precision - 4-band resistors are typically ±5% or ±10% tolerance, while 5-band resistors are commonly ±1% or better.

What if I can't tell gold from yellow, or the colors are faded?

A multimeter set to resistance mode is the most reliable way to confirm a resistor's actual value directly, especially for old, dirty, or hard-to-read components.

What does the tolerance range actually mean?

Manufacturing isn't perfectly precise, so the color code gives a nominal value plus a tolerance - a "1kΩ ±5%" resistor is guaranteed to actually measure somewhere between 950Ω and 1,050Ω, not exactly 1,000Ω.

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