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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:-

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.

If you cannot see the menu bar and logo at the top of the screen click here.

Enter Band colours:
Band A (1st digit)	Band B (2nd digit)	Band C (Multiplier)	Band D (Tolerance)

	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%