Resistor Color Code Calculator

Hold the resistor so the gold or silver tolerance band is on the right, then read left to right. The first two bands are digits, the third is the multiplier (a power of 10), and the fourth is tolerance. Brown, black, red, gold reads as 1, 0, x100, +/-5%, giving 1,000 ohms (1 kOhm).

A 4-band resistor gives 2 significant digits and covers most general-purpose parts. A 5-band adds a third digit, used on 1% and tighter precision resistors. A 6-band keeps the 5-band layout and adds a temperature coefficient band (in ppm/degC) as the sixth stripe, telling you how much resistance drifts as the part heats up.

It is a physical convention that helps you orient the part. Manufacturers space the tolerance band slightly apart from the digit and multiplier bands so you can tell which end to start reading from. If bands are evenly spaced, look for gold or silver: those colors never appear as a digit band, so they mark the tolerance end.

The meaning depends on which slot the color is in. As a multiplier, gold means x0.1 and silver means x0.01, used for low-ohm and fractional values (for example, 4 bands of yellow-violet-gold-gold decodes to 4.7 ohms, and yellow-violet-silver-gold gives 0.47 ohms). As a tolerance band, gold means +/-5% and silver means +/-10%. Neither color is ever a digit.

Real resistors are manufactured and sold in E-series preferred values (E12, E24, E96, and so on). This calculator decodes any color combination directly from the bands, including non-standard or legacy values that no distributor stocks. If the reading seems off, verify with a multimeter: the bands show the nominal value, not the actual measured resistance after manufacturing variation.