Resistor Color Code Calculator
Pick the colours of each band and the resistance appears instantly. Four-band resistors have two significant digits, five-band resistors have three, and six-band resistors add a temperature coefficient band. The coloured bands on a real resistor are read from the end where the bands are grouped closest together.
Method: resistance = (significant digits) × 10^(multiplier) · tolerance and temperature coefficient come from the last bands
Worked example: brown–black–red–gold is a 4-band resistor: digits 1 and 0, multiplier ×100, so 1,000 Ω (1 kΩ) ±5%. The same colours on a 5-band resistor (brown–black–black–red–gold) mean 100 × 100 = 10 kΩ ±5% — which is why counting the bands first matters.
Need the series resistor for an LED rather than a resistor value? Use the LED resistor calculator.
Frequently asked questions
How do I know which end to read from?
The tolerance band (gold, silver, or a lone band) sits slightly apart from the others — start from the opposite end. On 4-band resistors the first two bands are the digits; on 5-band, the first three.
What does tolerance actually mean?
A 1 kΩ resistor rated ±5% can measure anywhere from 950 Ω to 1050 Ω and still be in specification. For precision circuits choose 1% or better and check the temperature coefficient too.
What is the sixth band for?
Temperature coefficient — how much the resistance drifts per degree of temperature change, in parts per million per kelvin (ppm/K). It matters in precision and measurement circuits.