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Resistor Calculator

Decode the colour bands on a resistor to find its value and tolerance.

How it works Report a problem

Resistor Master

4-Band Color Code Solver

Resistance Value
1.0 kΩ
± 5%

About the Resistor Calculator

Decode the colour bands on a resistor to find its value and tolerance.

How to use the Resistor Calculator

  1. Choose the colour of the 1st Band (Digit), the 2nd Band (Digit), the 3rd Band (Multiplier) and the 4th Band (Tolerance).
  2. Read the resistance value shown.

Formula and method

Value = (first digit × 10 + second digit) × multiplier. Colours: black 0, brown 1, red 2, orange 3, yellow 4, green 5, blue 6, violet 7, grey 8, white 9.

Worked example

Brown, black, red = 10 × 100 = 1,000 Ω (1 kΩ).

Tips

  • Gold tolerance means ±5% and silver means ±10%.
  • Confirm with a multimeter when it matters.

Frequently asked questions

Which end do I start reading from?
Start from the end opposite the gold or silver tolerance band.