How do I read a resistor colour code?

Read the colour bands from the first significant digit band toward the tolerance and temperature coefficient bands. The first bands are digits, the multiplier scales the number, and the tolerance shows the allowable variation.

What is the tolerance of a 3-band resistor?

A 3-band resistor has no separate tolerance band, so its tolerance defaults to plus or minus 20 percent.

What is the difference between a 4-band and 5-band resistor?

A 4-band resistor uses two significant digits and a multiplier, while a 5-band resistor uses three significant digits and a multiplier. 5-band resistors are commonly used for precision values.