Resistor Color Code Calculator
Pick the color of each band to read off the resistance, tolerance, and temperature coefficient — live, in your browser.
Read any resistor color code
Through-hole resistors print their value as a series of colored bands. This calculator turns those bands back into a number: choose 4, 5, or 6 bands, set each band to the color printed on the part, and the resistance, tolerance, and (for 6-band parts) temperature coefficient update instantly. The first two or three bands are significant digits, the next band is a power-of-ten multiplier, the tolerance band tells you how far the real value may stray, and the optional sixth band gives the temperature coefficient in ppm/K.
The result is formatted with the usual SI suffixes — Ω, kΩ, MΩ, and GΩ — so a brown-black-red-gold resistor reads as 1 kΩ ±5%. Gold and silver also appear as multiplier bands (×0.1 and ×0.01) for sub-ohm values. Everything runs locally in your browser; nothing is uploaded.
FAQ
Which end do I read from? Read from the band closest to one end. The tolerance band (often gold or silver) is usually set slightly apart at the far end, so put it last.
What is the difference between 4, 5, and 6 bands? A 4-band resistor uses two significant digits; 5 and 6-band resistors use three for tighter precision. The sixth band adds a temperature coefficient.
What does the tolerance band mean? It is the maximum percentage the actual resistance may differ from the nominal value — for example ±5% on a 1 kΩ resistor means 950–1050 Ω.
Why are some colors missing from a band? Not every color is valid in every position. Gold and silver are only multipliers or tolerances, and black cannot be the first significant digit in practice.