Resistor Colour Code Calculator

Resistor Colour Code Calculator

Resistor colour code Calculator

Many through hole resistors are small in size because of used manufacturing material that the resistance value can’t be mentioned or unable to write on them. That’s why these resistors have colour bands that specify their values and tolerances.

On carbon-composition resistors and film resistors you can see there are three, four, five or six bands. Other type of resistors like wire wound resistors have large size, so that the resistance values can be printed on them in ordinary numerals.

For calculations of PCB Trace Resistance please visit, PCB Trace Resistance Calculator.

For calculations of Resistors for Voltage Divider please visit, Resistor Voltage Divider Calculator.

Resistor colour code calculator will help you to easily calculate the resistance value.

How to read resistor colour code?

Please refer below image, which will easily teach you the technique to find resistance value by reading colour bands on a resistor.

Resistor Colour Code

On resistors the first two bands signify the numbers 0 through 9; the third band signifies a multiplier of 10 to some power.

Suppose you get a resistor whose first three bands are in order red, violet, and red. Then the resistance is 2,700 Ω or 2.7 KΩ. Read red =2, violet =7, red =× 100.

If on a resistor there is a fourth band, it indicates the tolerance. If it’s silver, it means the resistor is rated at ±10 percent. If it’s gold, the resistor is rated at ± 5 percent. If there is no fourth band, the resistor is rated at ±20 percent.

If on a resistor there is a fifth band, it indicates the percentage that the value might change in 1,000 hours of use. A brown band specifies a maximum change of 1 percent of the rated value. A red band specifies 0.1 percent; an orange band specifies 0.01 percent; a yellow band specifies 0.001 percent. If there is no fifth band present on resistor, it means that the resistance of the resistor may deviate by more than 1 percent of the rated value after 1,000 hours of use.


While selecting a resistor designer cross check the resistor value before soldering it into the circuit because designer don’t want any adverse effect in the circuit or in the application. Reading the resistor colour code will help to find or select correct value of the resistance.

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