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Resistor Color Code Calculator: Read Any Resistor

This free resistor color code calculator reads the value of a resistor from its colored bands. Pick the number of bands and the color of each band to see the resistance, the tolerance and the range.

By Debmedia Technologies LLP · Kolkata, India · Updated

What Is It and When Do You Need It?

Small resistors are too tiny to print numbers on, so they use colored bands. Reading them takes a little practice and a chart. This calculator does it for you.

Choose the number of bands and the color of each.

How to Use This Tool

  1. Choose 4, 5 or 6 bands.
  2. Select the color of each band in order.
  3. Select the tolerance band.
  4. Press Calculate.

How the Calculation Works

In a 4-band resistor, the value is (digit 1 digit 2) × 10^multiplier. In a 5- or 6-band resistor, a third digit is added: (digit 1 digit 2 digit 3) × 10^multiplier. The tolerance gives the range of possible values. Gold and silver multipliers are 0.1 and 0.01.

Worked Example

Brown, black, red, gold (4 bands) is 10 × 100 = 1,000 Ω, or 1 kΩ ±5%. Yellow, violet, black, red, brown (5 bands) is 470 × 100 = 47,000 Ω, or 47 kΩ ±1%.

Common Uses

  • Electronics projects.
  • Repairing circuits.
  • Sorting components.
  • Learning electronics.

Tips and Common Mistakes

  • Measure with a multimeter to be sure.
  • The 3rd-digit selector is ignored on 4-band resistors.
  • Use standard values (E12, E24) when choosing parts.

Next, you may need the Ohm’s law calculator, LED resistor calculator, AWG wire gauge calculator, electricity cost calculator.

Everything runs in your browser. Nothing you type is uploaded, stored or sent to any outside service.

Frequently Asked Questions

The first two bands are digits, the third is the multiplier (the power of ten) and the fourth is the tolerance. Brown, black, red, gold is 1 0 × 100 = 1 kΩ ±5%.
Start with the band closest to one end. The tolerance band (gold or silver) is usually set slightly apart and is on the right.
Black 0, brown 1, red 2, orange 3, yellow 4, green 5, blue 6, violet 7, grey 8, white 9.
A temperature coefficient band. It is not included in the value, so this tool ignores it.

Disclaimer: results are calculated in your browser from the numbers you enter. Check important results before you rely on them for money, health, safety or legal decisions.