Resistor Color Codes

The electronic colour code for resistors was developed in the early 1920s, and allows coding on physically small components where printed text is difficult or impossible. Coloured markings are easier to read in 360 degrees without magnification, more resistant to abrasion, and still readable when chipped or partly obscured.

The idea is that coloured bands of different colours are painted on the resistor body, with each colour corresponding to a number. Tolerances are aslo colour coded. The first band is always closer to one end of the body, and the resistor value and tolerance are read from the bands. This system of colour markings is very common and in widespread use world wide.

  • Band A:- 1st significant digit (closest to the end)
  • Band B:- 2nd significant digit
  • Band C:- Multiplier (10^x)
  • Band D:- Tolerance (spaced further from the other bands)
for example, a resistor with 4 bands coloured:-
brown, red, green, gold
= 1st digit-1, 2nd digit-2, Multiplier-5 (=10^5 =100,000), tol-gold
= 120 kOhms 5%

See table below for values:-

Band values     Tolerance values
No. Colour Multiplier   Tol. Colour
0 Black x100 (1)      
1 Brown x101 (10)   1% Brown
2 Red x102 (100)   2% Red
3 Orange x103 (1,000)      
4 Yellow x104 (10,000)      
5 Green x105 (100,000)      
6 Blue x106 (1,000,000)      
7 Violet x107 (10,000,000)      
8 Grey x108 (100,000,000)      
9 White x109      
  Gold x10-1 (0.1)   5% Gold
  Silver x10-2 (0.01)   10% Silver
        20% None

A mnemonic for helping to remember these colours is:-
"Bad Boys Ravish Only Young Girls But Violet Gives Willingly"


Handy Resistor Calculator

To find the value of a resistor you have, enter the band colours in the boxes below:-

Enter Band colours:
Band A

(1st digit)
Band B

(2nd digit)
Band C

(Multiplier)
Band D

(Tolerance)

Value: ??


The standard 20% resistor values (E6) for one decade values are as follows:-
10, 15, 22, 33, 47, 68

The standard 10% resistor values (E12) for one decade values are as follows:-
10, 12, 15, 18, 22, 27, 33, 39, 47, 56, 68, 82

The standard 5% resistor values (E24) for one decade values are as follows:-
10, 11, 12, 13, 15, 16, 18, 20, 22, 24, 27, 30, 33, 36, 39, 43, 47, 51, 56, 62, 68, 75, 82, 91

Resistors have no polarity and can be connected either way.