Resistor Color Code Calculator
Decode 4-, 5- and 6-band resistor color codes into resistance, tolerance range and temperature coefficient — or enter a resistance and get the color bands to look for, per IEC 60062.
How it works
R = (significant digits) × 10^(multiplier) Ω · 4-band: 2 digits + multiplier + tolerance · 5-band: 3 digits + multiplier + tolerance · 6-band: 5-band + temperature coefficient · digits: black 0, brown 1, red 2, orange 3, yellow 4, green 5, blue 6, violet 7, grey 8, white 9 · gold ×0.1, silver ×0.01
Through-hole resistors are marked with colored bands defined by IEC 60062. Read from the end with the bands bunched together (the tolerance band, often gold or silver, is usually set apart on the right). The first two or three bands are significant digits, the next is the power of ten, then the tolerance; precision 6-band parts add a temperature coefficient in ppm per kelvin. In reverse mode the calculator rounds your value to the number of significant digits the band count can carry and tells you the colors.
Worked example
A 4-band resistor colored yellow, violet, red, gold reads 4 and 7 (= 47) × 10² = 4,700 Ω, i.e. 4.7 kΩ ±5%. Any part between 4.465 kΩ and 4.935 kΩ is within tolerance. The same value as a 5-band 1% resistor would be yellow, violet, black, brown, brown (470 × 10).
Sources: IEC 60062:2016 Marking codes for resistors and capacitors · Electronic color code — Wikipedia
Frequently asked questions
Which end do I start reading from?
Start from the end where the bands are closer together, or from the end opposite a gold or silver band — gold and silver are never first. If the body has a wider gap before one band, that band is the last (tolerance). When in doubt, measure with a multimeter: a reading that matches one orientation settles it.
What do gold and silver mean?
As a tolerance band gold is ±5% and silver ±10%. In the multiplier position gold means ×0.1 and silver ×0.01, used for resistors below 10 Ω — for example green, blue, gold = 56 × 0.1 = 5.6 Ω.
How do I read a 5-band or 6-band resistor?
The first three bands are digits, the fourth is the multiplier and the fifth the tolerance (usually brown ±1% or red ±2%). A sixth band gives the temperature coefficient, e.g. brown = 100 ppm/K: the resistance drifts by 0.01% per °C.
What is a resistor with a single black band?
A zero-ohm link — a wire jumper in a resistor body, used so that automated assembly machines can place jumpers like any other component.
Why does my value come out rounded in reverse mode?
A 4-band code carries only two significant digits (E6–E24 series), a 5- or 6-band code three (E48–E192). A value like 4,750 Ω needs three digits, so it shows on a 4-band part only as 4.7 kΩ or 4.8 kΩ — switch to 5 bands for the exact code.
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This calculator is for educational purposes. Double-check important results before acting on them.