The colors
| Black | 0 |
| Brown | 1 |
| Red | 2 |
| Orange | 3 |
| Yellow | 4 |
| Green | 5 |
| Blue | 6 |
| Violet | 7 |
| Gray | 8 |
| White | 9 |
As a multiplier, gold means × 0.1 and silver × 0.01. As a tolerance, gold is ±5%, silver ±10%, brown ±1% and red ±2%.
4-band resistors
Two digits, a multiplier and a tolerance. Brown, black, red, gold is 1, 0, × 100 = 1 kΩ ±5%. Yellow, violet, orange, gold is 47 × 1,000 = 47 kΩ ±5%.
5 and 6 bands
Precision resistors have three digits before the multiplier. Brown, black, black, brown, brown is 100 × 10 = 1 kΩ ±1%. A sixth band gives the temperature coefficient, how much the value drifts with heat, in ppm/K.
Which end first
The tolerance band is usually gold or silver and set a little apart from the others. Hold the resistor with it on the right. If you are unsure, check with a multimeter.
Calculator
Pick the bands in the Resistor Color Code Calculator to read the value. To work out what value you need, use the Ohm's Law Calculator or the LED Resistor Calculator.
Yellow, violet, orange, gold: 4, 7, then three zeros, so 47,000 Ω, which is 47 kΩ ±5%.
A 5-band worked example
Red, red, black, brown, brown: the digits are 2, 2, 0, the multiplier is × 10, and the last band is ±1%. 220 × 10 = 2.2 kΩ ±1%.
Is it backwards?
Resistors are made in standard series of values. The common E12 series runs 10, 12, 15, 18, 22, 27, 33, 39, 47, 56, 68 and 82, times a power of ten. If your reading gives digits outside the series, such as 74, you are probably reading from the wrong end.
Surface-mount resistors
Tiny chip resistors are printed with digits instead of bands. The last digit is the number of zeros: 472 is 47 followed by two zeros, 4.7 kΩ, and 1002 is 100 followed by two zeros, 10 kΩ. An R marks the decimal point: 4R7 is 4.7 Ω.