Resistor Color Code Calculator

How it works

The color code of IEC 60062 gives every color a digit: black 0, brown 1, red 2, orange 3, yellow 4, green 5, blue 6, violet 7, gray 8 and white 9. On a 4-band resistor the first two bands are digits and the third is a multiplier, a power of ten; on 5- and 6-band resistors the first three bands are digits and the fourth is the multiplier. Gold and silver as multipliers mean ×0.1 and ×0.01, which is how values below 10 Ω are marked.

The band after the multiplier is the tolerance: how far the actual resistance may lie from the marked value. A 4-band resistor with no tolerance band is a ±20% part. The lowest and highest values shown are the marked value minus and plus that percentage.

A 6-band resistor adds a temperature coefficient band, the change in resistance per kelvin of temperature change in parts per million. Some precision 5-band parts carry the same information as an interrupted band between the fourth and fifth band. Orange (±15 ppm/K) and yellow (±25 ppm/K) are decoded from a manufacturer's data sheet; for any other color the calculator uses the value entered from the part's own data sheet.

In the other direction, a value is split into two significant digits (4 bands) or three (5 and 6 bands) and a power of ten from 10^-2 to 10^7. A value that needs more digits than the band count allows, such as 4.75 kΩ on a 4-band part, cannot be marked exactly; the message names the nearest IEC 60063 preferred value that can be, from the E24 series for 4 bands or the E96 series for 5 and 6 bands (4.7 kΩ and 4.75 kΩ in this case).

Formula

4 bands:  R = (10 × d1 + d2) × 10^m
5/6 bands: R = (100 × d1 + 10 × d2 + d3) × 10^m
d = digit color: black 0 … white 9
m = multiplier: silver −2, gold −1, black 0 … violet 7
lowest  = R − R × t ÷ 100
highest = R + R × t ÷ 100     (t = tolerance in %)

Example

Yellow, violet, red, gold: the digits 4 and 7 make 47, red multiplies by 10^2, so R = 4,700 Ω = 4.7 kΩ. Gold is ±5%, a deviation of 235 Ω, so the resistor may measure from 4.465 kΩ to 4.935 kΩ.

Green, blue, red, black, violet with an interrupted yellow band: 562 × 10^0 = 562 Ω, ±0.1% (561.438 Ω to 562.562 Ω), ±25 ppm/K.

Going the other way, 4.7 kΩ on a 5-band resistor is 470 × 10^1: yellow, violet, black, brown, then the tolerance band.

Assumptions and limitations

• Colors, multipliers and tolerances follow the color code table in Electronics Tutorials, "Resistor Colour Code" (© 2026 AspenCore). Gray and white multipliers, pink, and the rarer tolerance colors gray, orange and yellow are not decoded.
• Temperature-coefficient colors orange (±15 ppm/K) and yellow (±25 ppm/K) are taken from Vishay Beyschlag's MMU 0102 / MMA 0204 / MMB 0207 data sheet (document 28963, revision 02-Jun-2026). Other temperature-coefficient colors are not built in; the value entered for Another color is taken as given.
• The bands are taken in the order entered; the calculator cannot tell which end of a part carries the first band, and a faded band can be misread as a neighboring color.
• Tolerance is the allowed deviation when the part is new, at the reference temperature. Drift with temperature, load and age is not included in the lowest and highest values.
• The result is a decoding of the marking, not a substitute for the manufacturer's data sheet for the specific part.

Frequently asked questions