Resistor Color Code Calculator
Contents
Below is a resistor color code calculator. Simply choose the color of each band, and it works out the resistor’s resistance, its tolerance and the allowed range of values within that tolerance. For 6-band resistors you also get the temperature coefficient.
How to read the bands
Read the resistor from left to right, with the tolerance band on the right. It is usually set slightly apart from the others and is often gold or silver. Gold and silver are never the first digit, so if a resistor has a gold or silver band at one end, turn it so that band is on the right.
- 4 bands: two digits, a multiplier and the tolerance. Most common on ordinary carbon resistors with ±5% tolerance.
- 5 bands: three digits, a multiplier and the tolerance. Typical for metal film resistors with ±1% tolerance or better.
- 6 bands: as with 5 bands, plus a last band for the temperature coefficient, i.e. how much the resistance changes with temperature.
To get the value, write the digits next to each other and multiply by the multiplier. For example, yellow, violet, red, gold means 4 and 7, times 100, so 4700 Ω = 4.7 kΩ ±5%.
Color table
| Color | Digit | Multiplier | Tolerance | Temp. coefficient |
|---|---|---|---|---|
| black | 0 | ×1 | – | ±250 ppm/K |
| brown | 1 | ×10 | ±1% | ±100 ppm/K |
| red | 2 | ×100 | ±2% | ±50 ppm/K |
| orange | 3 | ×1 k | ±0.05% | ±15 ppm/K |
| yellow | 4 | ×10 k | ±0.02% | ±25 ppm/K |
| green | 5 | ×100 k | ±0.5% | ±20 ppm/K |
| blue | 6 | ×1 M | ±0.25% | ±10 ppm/K |
| violet | 7 | ×10 M | ±0.1% | ±5 ppm/K |
| grey | 8 | ×100 M | ±0.01% | ±1 ppm/K |
| white | 9 | ×1 G | – | – |
| gold | – | ×0.1 | ±5% | – |
| silver | – | ×0.01 | ±10% | – |
| pink | – | ×0.001 | – | – |
| no band | – | – | ±20% | – |
Values follow IEC 60062:2016 (see Standards and sources).
The digits 2 to 7 follow the order of the rainbow: red, orange, yellow, green, blue, violet. Black (0) and brown (1) come before them, grey (8) and white (9) after. Once you remember that, you hardly need the table.
Grey tolerance
Until 2016, grey as a tolerance band meant ±0.05%; under the current standard it means ±0.01%. On older precision resistors, grey almost certainly means ±0.05%.
E standard series
Resistors are not made in every value, but in standard series. The number in the series name tells how many values there are in one decade: E12 has 12 values (1.0, 1.2, 1.5, 1.8, 2.2, 2.7, 3.3, 3.9, 4.7, 5.6, 6.8, 8.2), E24 has 24, and so on. The tighter the tolerance, the denser the series: E12 is typical for ±10%, E24 for ±5%, and E96 for ±1%.
If the calculator says a value is not in any series, a color was probably misread.
Standards and sources
Before the color code, every manufacturer marked resistors its own way. The color code was created in the US in the 1920s by the Radio Manufacturers Association (RMA), and the first radios with resistors marked this way appeared around 1930. Colors were chosen because bands are easy and cheap to print on a small cylindrical body and can be read from any angle, unlike tiny printed numbers.
The code later became an international standard:
- IEC 60062, Marking codes for resistors and capacitors. It defines what the colors mean: digits, multipliers, tolerances and temperature coefficients. The first edition was IEC 62 from 1952. The current version is the 2016 edition with amendment A1:2019; the 2016 edition also introduced pink for the ×0.001 multiplier. In Europe it is adopted as EN 60062.
- IEC 60063, Preferred number series for resistors and capacitors. It defines the E6–E192 standard series. The current edition is from 2015.
- EIA RS-279, an older US standard with the same colors. It differs in the grey tolerance, which means ±0.05% there.
The standards are paid documents, available from the IEC webstore or from national standards bodies. A free and quick way to confirm the code is the resistor manufacturer’s datasheet, which always lists the color code for that series.