Reading the bands

Resistors are too small to print numbers on, so their value is coded in colored bands, defined in the international standard IEC 60062. Hold the resistor with the band group on the left. The tolerance band, usually gold, silver or brown, is often slightly separated from the others and goes on the right.

Color	Digit	Multiplier	Tolerance	Tempco
Black	0	×1		250 ppm/K
Brown	1	×10	±1%	100 ppm/K
Red	2	×100	±2%	50 ppm/K
Orange	3	×1k	±0.05%	15 ppm/K
Yellow	4	×10k	±0.02%	25 ppm/K
Green	5	×100k	±0.5%	20 ppm/K
Blue	6	×1M	±0.25%	10 ppm/K
Violet	7	×10M	±0.1%	5 ppm/K
Grey	8	×100M	±0.05%	1 ppm/K
White	9	×1G
Gold		×0.1	±5%
Silver		×0.01	±10%
None			±20%

4, 5 and 6 bands

4 bands: digit, digit, multiplier, tolerance. Yellow, violet, red, gold is 4, 7, ×100 = 4.7 kΩ ±5%.
5 bands: three digits, multiplier, tolerance, used for precision parts. Brown, black, black, brown, brown is 1, 0, 0, ×10 = 1 kΩ ±1%.
6 bands: like 5 bands, plus a temperature coefficient (tempco) at the end. Brown there means the value drifts by at most 100 parts per million for every kelvin (or °C) of temperature change.

Choose the band count at the top, then click a color under each band. The drawing, resistance, tolerance and range update at once, and the URL updates too, so you can bookmark or share a reading.

From a value to colors

Type a value into Value to bands and press Find bands. The tool accepts:

plain numbers: 470, 22000
suffixes: 4.7k, 1M, 2.2G
the "R" notation printed on schematics, with the letter as the decimal point: 4k7 = 4.7 kΩ, 1R5 = 1.5 Ω

If the value needs more significant digits than the band count allows, it's rounded to the closest value the bands can show, and you're told. For example, 4.75k becomes 4.8k on a 4-band resistor, but fits exactly on 5 bands.

Tolerance and range

Tolerance is how far the real value may differ from the marked one. The range shows the limits: a 4.7 kΩ ±5% resistor measures between 4.465 kΩ and 4.935 kΩ. If your multimeter reads inside that window, the resistor is fine.

Standard values (E-series)

Resistors are made in preferred values that are spaced evenly on a logarithmic scale, so each tolerance band overlaps the next:

E12 (12 values per decade): 10, 12, 15, 18, 22, 27, 33, 39, 47, 56, 68, 82
E24 (24 per decade): E12 plus 11, 13, 16, 20, 24, 30, 36, 43, 51, 62, 75, 91
E96 (96 per decade): used for 1% parts, from 100, 102, 105 up to 976

Under the result, the calculator tells you whether your value is standard and which series it belongs to. If it isn't, it names the nearest E24 value, plus the nearest E96 value for 1% parts. That helps when a circuit calls for an odd value like 4.6 kΩ: buy 4.7 kΩ (E24) or 4.64 kΩ (E96).

Tips for reading real resistors

Which end is which? Gold and silver never appear as the first band. If neither end is gold or silver, the end band closer to the edge is usually the first.
Brown, red and orange look alike under warm light. Check under daylight or use a multimeter.
Burnt resistors change color. Read the value from the schematic instead.
SMD resistors don't use bands. They use printed codes like 472 (4.7 kΩ) or 01C (EIA-96).

Need base conversions for a microcontroller register? Use the hex calculator and hex to decimal converter. For a different kind of color code, see the Minecraft color codes editor. The color name finder names any shade you see.

FAQ

What does a zero-ohm resistor look like?

A single black band. It's a jumper wire in a resistor body, used so assembly machines can place links like any other part.

Is grey tolerance 0.05% or 0.01%?

Charts disagree. Many list grey as ±0.05%, which this calculator uses, while some recent references use ±0.01%. Grey tolerance bands are rare in practice, so check the datasheet.

Why is my 5-band reading 10 times too big?

You probably read it as a 4-band resistor, or from the wrong end. Count the bands again and start from the end without the gold, silver or wider-spaced band.