Resistor Colour Code Calculator
Read 4-, 5- and 6-band resistor colour codes to a value, tolerance range and temperature coefficient, or turn a value into its bands, with the E-series checked.
The resistance a marked resistor has and the range it may actually fall in — or the bands to look for — with every band’s role named per IEC 60062.
Example: Yellow, violet, red, gold reads 47 × 100 = 4.7 kΩ ±5 %, so anywhere from 4,465 to 4,935 Ω. Five bands brown, black, black, red, brown are 10 kΩ ±1 %.
Digits, multiplier, tolerance.
Read from the end without the gap.
How the bands are read, what four, five and six bands each add, and how to tell which end is first.
The code
Each colour stands for a digit — black 0, brown 1, red 2, orange 3, yellow 4, green 5, blue 6, violet 7, grey 8, white 9. A four-band resistor has two digit bands, a multiplier band (the same colours as powers of ten, plus gold ×0.1 and silver ×0.01) and a tolerance band (gold ±5 %, silver ±10 %, brown ±1 %, red ±2 %, and so on). Five bands add a third digit for precision values; a sixth band gives the temperature coefficient in ppm per kelvin. The page names the role of every band it read, so a misread is easy to spot.
Which end is first
The tolerance band is usually set apart by a wider gap and sits at one end; the digit bands start from the other end. Gold and silver are never digits, so a resistor that reads “gold first” is being read backwards — the page refuses such a reading with a message rather than guessing. When a reading is not a preferred E12, E24 or E96 value the page says so, which usually means two bands were swapped or a colour misjudged (red/orange and brown/violet are the usual culprits under poor light).
Tolerance range and encoding
The tolerance is a guarantee from the maker, not a typical error: a 4.7 kΩ ±5 % part may measure anywhere from 4,465 to 4,935 Ω, and the range is shown so a measured value can be judged. Encoding a value produces the bands for two or three significant figures; a value that needs more figures than the band count allows is refused rather than silently rounded.
Privacy
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SOURCES
- IEC 60062:2016, Marking codes for resistors and capacitors — colour code for resistance, tolerance and temperature coefficient
- IEC 60063:2015, Preferred number series for resistors and capacitors — E12, E24, E96
Last reviewed 19 September 2026. How results are checked: How we verify.