On resistors with four colour bands, which colour band specifies the tolerance?

On a standard four-band resistor, the fourth color band indicates the component's tolerance. This tells you the maximum percentage by which the actual resistance might vary from the marked value, most commonly represented by gold (5%) or silver (10%). When reading a resistor, the first two bands represent the first two significant digits of the resistance value, and the third band serves as the multiplier (the number of zeros to append). The tolerance band is usually spaced slightly further away from the other three.