Calculator
Resistor Color Code Calculator
Pick the four color bands to read a resistor’s value.
How do resistor color codes work?
Small resistors are too tiny to print numbers on legibly, so manufacturers use a standardized color band system instead (IEC 60062). On a 4-band resistor, the first two bands are significant digits, the third is a multiplier, and the fourth is the tolerance — read together, they give you the resistance value without a multimeter.
Frequently asked questions
How do I read the four bands?
Band 1 and band 2 are digits 0-9 that combine into a two-digit number. Band 3 is a multiplier — it tells you how many zeros to add (or a fractional multiplier for gold/silver). Band 4 is tolerance, showing how far the actual resistance may vary from the printed value.
What does the tolerance band mean?
It's the manufacturer's guaranteed accuracy range. A gold band means ±5%, silver means ±10%, and no fourth band at all traditionally means ±20%. A resistor marked 100Ω with a gold tolerance band could actually measure anywhere from 95Ω to 105Ω.
What about 5-band or 6-band resistors?
This calculator covers the common 4-band case. 5-band resistors add a third digit for higher precision (used in precision resistors), and 6-band resistors add a temperature coefficient band on top of that — both follow the same color-to-number logic, just with an extra digit or spec.
Is there a trick to remembering the color order?
The classic mnemonic runs black-brown-red-orange-yellow-green-blue-violet-gray-white for digits 0 through 9 — many people learn it as a phrase where each word's first letter matches a color in order. With practice, most electronics hobbyists stop needing it and just recognize common values on sight.