Resistor color code
The resistance of a resistor can be calculated with the color of the bands. Most resistors have four bands, but there are also resistors with three, five, and six bands. SMD resistors use numbers instead of colors. You can find more information about the SMD codes here
The first and second band represent significant digits and form a number between 00 and 99. This number gets multiplied by the multiplier, which is represented by the last band.
The first and the second band both represent a significant digit. These are added together to form a number between 00 and 99. The third band represents the multiplier. The number is multiplied by ten to the power of the value of the third band. The fourth band represents the tolerance of the resistor. This is given as a percentage and indicates the error your resistor might have.
Five band resistors are similar to their four band counterparts, the only difference is that five band resistors have an additional significant digit. Five band resistors can, therefore, have three significant digits and are more precise.
Six band resistors work the same as five band resistors. However, they have another band at the end which indicates the temperature coefficient of resistance (TCR). The TCR determines the change in resistance as a function of the temperature.
Color code table