Resistor Color Code Calculator

How the resistor color code works

Small through-hole resistors are too tiny to print numbers on, so their value is shown with colored bands. Each color stands for a digit: black 0, brown 1, red 2, orange 3, yellow 4, green 5, blue 6, violet 7, gray 8 and white 9. On a 4-band resistor the first two bands are the significant digits, the third band is the multiplier and the fourth band is the tolerance. For example brown, black, red, gold reads as 1, 0 × 100 = 1,000 ohms, or 1 kΩ with a ±5 percent tolerance.

4, 5 and 6 band resistors

Precision resistors use five bands: three digits, a multiplier and a tolerance, such as ±1 percent for brown. A sixth band adds the temperature coefficient, which tells you how much the resistance drifts per degree Celsius in parts per million. This calculator draws the resistor as you select colors, shows the value in ohms, kilo-ohms or mega-ohms, and gives the minimum and maximum resistance allowed by the tolerance so you can check whether a part fits your design.

Reading tips and common mistakes

The tolerance band is usually gold or silver and sits slightly apart from the others, which tells you the reading direction. If you are unsure, compare both directions and see which one gives a standard value from the E12 or E24 series. Brown and red, and orange and red, can look alike in poor light, so confirm with a multimeter if the result matters. Gold and silver can only be multipliers or tolerance colors, never digits. Everything here runs locally in your browser, with no data sent anywhere.

Example: yellow, violet, orange, gold is 4, 7, × 1,000, so 47 kΩ with ±5 percent tolerance, meaning the real value lies between 44.65 kΩ and 49.35 kΩ. A 5-band resistor marked red, red, black, brown, brown is 220 × 10 = 2.2 kΩ at ±1 percent.