Tool · Electrical
Resistor Colour Code
Pick the colour bands and read the value, tolerance and temperature coefficient – or enter a value and see which bands belong to it and which standard value is closest. For resistors with 4, 5 and 6 bands.
What it is for
- Sorting parts: identify loose resistors from a drawer or a kit without measuring each one.
- Repairs: read the value of a resistor on a circuit board so you can get a replacement.
- Planning: a calculated value – such as a series resistor from the Ohm’s Law Calculator – can rarely be bought. The tool shows the nearest standard value and which bands it carries.
Where is band 1?
The standard for the colour code, IEC 60062, says that the first band should, where possible, sit closest to one end of the resistor, and that the bands should be spaced so they cannot be misread. The tolerance band is at least one and a half times as wide as the others. In practice, these help:
- Gold and silver are never first – they have no digit. If one of them is at the edge, read from the other end.
- Band 1 is closer to its end than the last band is to the other end.
- If one direction gives a value that is in no E series, the other direction is probably right. The tool shows you what you would get reading backwards.
4, 5 or 6 bands
- 4 bands: two digits, multiplier, tolerance.
- 5 bands: three digits, multiplier, tolerance – common for tighter tolerances.
- 6 bands: as 5 bands, plus one band for the temperature coefficient (TCR or tempco): how much the resistance changes per kelvin of temperature change, in ppm/K (parts per million per kelvin).
What each colour means depends on its position:
| Colour | Digit | Multiplier | Tolerance | Tempco |
|---|---|---|---|---|
| Black | 0 | ×10⁰ | – | 250 ppm/K |
| Brown | 1 | ×10¹ | ±1 % | 100 ppm/K |
| Red | 2 | ×10² | ±2 % | 50 ppm/K |
| Orange | 3 | ×10³ | – | 15 ppm/K |
| Yellow | 4 | ×10⁴ | – | 25 ppm/K |
| Green | 5 | ×10⁵ | ±0.5 % | 20 ppm/K |
| Blue | 6 | ×10⁶ | ±0.25 % | 10 ppm/K |
| Violet | 7 | ×10⁷ | ±0.1 % | 5 ppm/K |
| Grey | 8 | ×10⁸ | ±0.05 % | 1 ppm/K |
| White | 9 | ×10⁹ | – | – |
| Gold | – | ×10⁻¹ | ±5 % | – |
| Silver | – | ×10⁻² | ±10 % | – |
| Pink | – | ×10⁻³ | – | – |
| no band | – | – | ±20 % | – |
Pink as a multiplier of 10⁻³ was added in the 2016 edition of the standard; you will hardly find it on older resistors. “No band” means the fourth band is missing and the resistor has only three.
Worked examples
Yellow – violet – red – gold
- Digits: yellow = 4, violet = 7 → 47
- Multiplier: red = ×10² → 47 × 100 = 4,700 Ω = 4.7 kΩ
- Tolerance: gold = ±5 % → anything from 4,465 Ω to 4,935 Ω is within tolerance
Red – yellow – white – orange – brown
An example from the standard itself: three digits 2, 4, 9 → 249, multiplier orange = ×10³ → 249 kΩ, tolerance brown = ±1 %.
E series: why there is no 157.5 Ω resistor
Resistors are made in fixed series of values, the E series. The number says how many values there are per decade: E12 has 12, E24 has 24, E96 has 96, E192 has 192. Neighbouring values are roughly a factor of ¹²√10 (E12), ²⁴√10 (E24) and so on apart. The series go together with the tolerance:
- E12 – ±10 %
- E24 – ±2 % and ±5 %
- E96 – ±1 %
- E192 – ±0.5 %, ±0.25 % and ±0.1 %
The values of each series repeat in every decade: 4.7 Ω, 47 Ω, 470 Ω, 4.7 kΩ and so on. The calculated series resistor of 157.5 Ω (example in the Ohm’s Law Calculator) lies between 150 and 160 Ω in the E24 series – the second part of the tool opens with exactly that value.
Common mix-ups
- Red and orange look alike under artificial light – a factor of 10 in the multiplier.
- Brown, black and violet are hard to tell apart on dark bodies.
- Gold and yellow or orange are easily confused on small resistors.
- Resistors that have run hot for a long time can be discoloured.
If in doubt, measure: take the resistor out of the circuit (or desolder one leg), set the multimeter to ohms and read the value. It should be within the tolerance.
If you tinker often, a resistor kit pays off: values from the E12 or E24 series, sorted. Then the nearest standard value is usually already in the drawer.
Looking ahead: SMD resistors
Tiny SMD resistors carry no bands but a printed code of digits and letters. IEC 60062 covers those codes as well, including a separate code for the values of the E96 series. This tool does not read them (yet).
Limits of this tool
- The colours on screen are a representation, not a colour measurement. Whether a band is red or orange is something you decide by looking at the part.
- It knows the IEC 60062 colour code for 4, 5 and 6 bands. Manufacturer-specific codes and SMD codes are not covered.
- The tolerance describes the deviation as manufactured. Ageing, heat and load come on top.
Privacy: the calculator runs entirely in your browser. What you enter is not sent to xmoo.app or anyone else.
Sources
- Colour code with digits, multipliers, tolerances and temperature coefficients, layout with 4, 5 and 6 bands: Panasonic Industry, Color Code (to IEC 60062)
- Position of band 1, width of the tolerance band, pink for 10⁻³, examples 6.8 kΩ ±20 %, 750 kΩ ±5 % and 249 kΩ ±1 %, SMD codes: IEC 60062:2016, preview at VDE Verlag
- E series E12, E24, E96, E192 with all values and their tolerances: Vishay, Standard Electronic Decade Value Tables; based on IEC 60063
Page last updated: 31 October 2026