A look into the electronic circuit board mostly shows wires with colorful bands, called resistors. These color bands indicate the values of those resistors like the identity card does for us. With these color bands, we can identify the resistive value and its percentage tolerance of a resistor.

 For large power resistors, the resistor body is big enough to print the resistance value, tolerance, and wattage rating on them. But for small rating resistors say 0.25 W resistors are very small in size and it’s difficult to print its value directly onto the component surface. Hence a standard was formed in 1920 by the Radio Manufacturers Association (now part of EIA – Electronic Industries Alliance) to identify values and ratings of electronic components by printing color codes on them.

For example a 100 ohms resistor or a 1-kilo ohms resistor with 5% tolerance.  The color-coding technique makes it easy to print values (based on color codes) on small components, such as resistors and facilitates cost-effective manufacturing.

What is Color Coding?

“Color coding” is used in electronics to identify between different components. In the case of resistors, color coding is used to identify a specific resistance value, for example, a 100 ohms resistor or a 1-kilo ohms resistor with 5% tolerance. Electronic components like resistors are very small in size and it’s difficult to print their value directly onto the component surface. Hence a standard was formed in 1920 by the Radio Manufacturers Association (now part of EIA – Electronic Industries Alliance) to identify values and ratings of electronic components by printing color codes on them.  The color-coding technique makes it easy to print values (based on color codes) on small components, such as resistors and facilitates cost-effective manufacturing.

This technique of “color coding” has 2 disadvantages. The first one appeals to general users where it becomes difficult to distinguish between colors (for example “Red” and “Brown” ) when the component is overheated. But this is not a major concern as the exact value can be easily identified using a multimeter (in case of confusion). The next drawback is for a specific group of people – color blind people can not identify the device using color codes. However, they too can depend on a multimeter to identify resistance values.

How to Identify Resistor Color Code

The figure below shows the layout of the bands, the multiplier, and the tolerance value of a resistor. For a 6-band resistor, an additional temperature coefficient band is provided.

The gap between the multiplier and the tolerance specifies the left and right sides of the resistor.  So here are the key points;

4 band resistor – has 3 color bands on the left side and one color band on the right side. The first two bands represent significant digits, the 3rd band represents multiplier and the fourth band on the right side represents tolerance.

5 band resistor  – has 4 color bands on left side and one color band on right side. Here the first 3 color bands represent significant digits, fourth one represent multiplier and the 5th one on right side represents tolerance.

6 band resistor – has 4 color bands on the left side and 2 color bands on the right side. Here the first 3 color bands represent significant digits, the fourth one represents multiplier, the 5th one represents tolerance and the 6th one represents the temperature coefficient of the resistor.

In a 4-band resistor, the first two bands represent the first two digits of the resistor. The multiplier band indicates the value that is to be multiplied with the first two digits. The tolerance band after the multiplier band indicates the range of accuracy of the resistor. It is represented in units of percentage.  In the case of 5 band resistor,  the decimal multiplier will be assigned to the fourth band and the tolerance value will be assigned to the fifth band. Finally, in the case of a 6 band resistor, the last band (i.e 6th band) represents the temperature coefficient. The sixth temperature coefficient band increases the precision of the resistance value. Temperature coefficient tells us the behavior of resistors under different heating conditions (means the variation in resistance values under normal conditions and overheated conditions)It is defined in units of ppm/K.

Resistor Color Code Chart

We have presented 3 charts below – which are exactly resistor color code charts for 4 band, 5 band and 6 band resistors respectively.

4-Band Resistor Color Code Identification

Let us consider the color code for the resistor with the bands BROWN-BLACK-RED-GOLD. Brown corresponds to the value ‘1’ in the color chart. Black represents ‘0’ and Red represents the multiplier ‘100’. Thus the value of the resistance to the corresponding color code is 10*100 = 1000 ohms or 1 kilo ohm with the tolerance band being Gold which represents a tolerance of +/- 5%. Thus, the actual value of the 1 kilo ohm can be between 950 ohms and 1050 ohms.

4 Band Resistor Color Coding Chart

Band 1 – First digit value of resistor

Band 2 – Second digit value of resistor

Band 3 – Decimal Multiplier

Band 4 – Tolerance Value

5-Band Resistor  Color Code Identification

Let us consider the color code for the resistor with the bands YELLOW-VIOLET-BLACK-BROWN-GREY. Yellow corresponds to the value ‘4’ in the color chart. Violet represents ‘7’ and Black represents the value ‘0’.  Brown represents the multiplier ‘10’. Thus the value of the resistance to the corresponding color code is 470*10 = 4700 ohms or 4.7-kilo ohm with the tolerance band being Grey which represents a tolerance of +/- 0.05%.

5 Band Resistor Color Code

Band 1 – First digit value of resistor

Band 2 – Second digit value of resistor

Band 3 – Third digit value of resistor

Band 4 – Decimal Multiplier

Band 5 – Tolerance Value

 6-Band Resistor Color Code Identification

Here also, if we can consider the same color code used for the 5-band, with an additional temperature coefficient band with a blue color. This shows that the resistor has a value of 4.7 kilo ohms, with tolerance +/- 0.05% and with a temperature coefficient of 10 ppm/K.

6 Band Resistor Color Code

Band 1 – First digit value of resistor

Band 2 – Second digit value of resistor

Band 3 – Third digit value of resistor

Band 4 – Decimal Multiplier

Band 5 – Tolerance Value

Band 6 – Temperature Coefficient

 Note:- Nowadays with advances in printing technology, it’s possible to print numeric values on small components as well. If you look at an SMD resistor (surface mount), you will see the resistance value printed directly on the surface of the resistor.

In a Nutshell

Colour coding helps us find out the value of resistors easily. Color coding is also used in other electronic components like inductors, capacitors, and others as well. Nowadays, with advances in printing technology, it is possible to print numeric values on small components as well, like the one you see on an SMD resistor (surface mount resistor) where the resistance values are printed using a three-digit code. Here the first two digits indicate its resistance value and the third digit its multiplier.
However, color coding still holds on to its popularity. Since it is quite difficult to remember such a code, many mnemonics have been curated to memorize the order of the colors. Two of the popular mnemonics are “BBROYGreatBritainVeryGoodWife” and “BigBoysRaceOurGirlsButVioletGenerallyWins”. Each of the first letters represents the string of colors BBROYGBCGW that is Black, Brown, Red, Orange, Yellow, Green, Blue, Violet, Grey, and White.

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6 Comments

  1. The tolerance band colours listed above appear to be incorrect, especially if you are in North America. Resistor colour codes usually follow the standard IEC 60062, and there are others (JIS C 0802, JSS 50401, etc.). 4-band and 5-band resistors usually only use tolerances of Brown 1%, Red 2%, Gold 5%, or Silver 10%. 6-band resistors can include greater precision with tolerances of Green 0.5%, Blue 0.1%, or Violet 0.1%. Yellow and grey are typically avoided because they look like gold and silver, and in fact they are used to replace gold and silver on resistors that must not contain metallic paint. (Orange is not used for 3% and yellow is not used for 4%.)

  2. Thank you very much for your sharing of the knowledge. It’s important to understand the colour code of the Resistor for a electronic hobbies.