Value to colors (reverse lookup)
Type a resistance such as 5000, 4.7k, 4k7 or 2.2M (k = kilo, M = mega). The tool picks the nearest E12 or E24 standard value and shows its bands for the band count selected above.
Resistor color code chart
The IEC 60062 band colors with their digit, multiplier, tolerance and temperature coefficient (TCR) meanings. On a 4-band resistor, bands 1 and 2 are digits; on 5- and 6-band resistors, bands 1 to 3 are digits. The next band is the multiplier, then tolerance, then (6-band only) the temperature coefficient.
| 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 | ×1k | ±0.05% | 15 ppm/K |
| Yellow | 4 | ×10k | ±0.02% | 25 ppm/K |
| Green | 5 | ×100k | ±0.5% | 20 ppm/K |
| Blue | 6 | ×1M | ±0.25% | 10 ppm/K |
| Violet | 7 | ×10M | ±0.1% | 5 ppm/K |
| Grey | 8 | ×100M | ±0.01% | 1 ppm/K |
| White | 9 | ×1G | – | – |
| Gold | – | ×0.1 | ±5% | – |
| Silver | – | ×0.01 | ±10% | – |
| None | – | – | ±20% | – |
Memory aid
The digit colors 0 to 9 run black, brown, red, orange, yellow, green, blue, violet, grey, white. One neutral way to remember them: Better Be Right Or Your Great Big Venture Goes Wrong. The middle stretch, red to violet, is the rainbow order (ROY G BIV).
E12 and E24 standard values (IEC 60063)
Standard resistor values repeat in every decade: multiply by 1, 10, 100, 1k and so on. E12 is traditionally paired with ±10% tolerance and E24 with ±5%.
| E12 | E24 | |
|---|---|---|
| 1.0 | 1.0 | 1.1 |
| 1.2 | 1.2 | 1.3 |
| 1.5 | 1.5 | 1.6 |
| 1.8 | 1.8 | 2.0 |
| 2.2 | 2.2 | 2.4 |
| 2.7 | 2.7 | 3.0 |
| 3.3 | 3.3 | 3.6 |
| 3.9 | 3.9 | 4.3 |
| 4.7 | 4.7 | 5.1 |
| 5.6 | 5.6 | 6.2 |
| 6.8 | 6.8 | 7.5 |
| 8.2 | 8.2 | 9.1 |
Source: thealltools.com/tools/resistor-color-code-calculator
About this tool
This resistor color code calculator decodes 4-band, 5-band and 6-band resistors. It shows the resistance, the tolerance range and, on 6-band parts, the temperature coefficient. It also works in reverse: type a value and it finds the nearest E12 or E24 standard value and the bands that mark it. The color meanings follow IEC 60062, the international standard for resistor and capacitor marking codes. A printable chart of every color and the E12/E24 values sits just above this section. Everything runs in your browser.
How to use the resistor color code calculator
- Choose the band count. Count the colored rings on the part. Three rings means a 4-band code with no tolerance band (pick None for band 4, which means ±20%).
- Hold the resistor the right way round. Gold and silver are never digit colors, so a gold or silver band is never the first band. On many parts the tolerance band also sits a little apart from the others.
- Set each band. Click a band on the drawing (or a band's drop-down), then click a color in the palette. After each pick, the palette moves on to the next band.
- Read the result. The value, tolerance, minimum and maximum, and temperature coefficient update as you go.
- For the reverse lookup, type a value, choose E12 or E24 and press Find bands. Apply to resistor copies the result onto the drawing.
How the color code works
Each color stands for a number. The digit bands are read as a whole number, which is multiplied by the multiplier band's power of ten:
4-band: R = (d1 d2) × multiplier tolerance = band 4 5-band: R = (d1 d2 d3) × multiplier tolerance = band 5 6-band: same as 5-band, plus band 6 = temperature coefficient (ppm/K)
Black through white are the digits 0 to 9. As a multiplier, each color is 10 raised to its digit, so red is ×100 and orange is ×1,000. Gold (×0.1) and silver (×0.01) produce values below 10 Ω. In the tolerance position, gold means ±5%, silver ±10%, brown ±1% and red ±2%. The full table, including the IEC 60062:2016 precision tolerances for orange, yellow and grey, is in the chart above. The temperature coefficient tells you how much the resistance drifts with temperature. Brown, at 100 ppm/K, means up to 0.01% change per kelvin.
The color values in this tool come from the Panasonic resistor color code table, which follows IEC 60062. They were cross-checked against the IEC 60062 table summarized on Wikipedia.
Worked example
The tool opens on a 4-band resistor colored yellow, violet, red, gold. Yellow is 4 and violet is 7, which gives 47. Red as a multiplier is ×100, so 47 × 100 = 4,700 Ω, or 4.7 kΩ. Gold in the tolerance position is ±5%, so a good part measures between 4.465 kΩ and 4.935 kΩ.
The reverse lookup starts with 5000 and the E24 series. 5 kΩ is not a standard value. The closest E24 value is 5.1 kΩ (2% above), and its bands are green, brown, red plus the current tolerance band (gold). With E12 selected, the nearest value is 4.7 kΩ instead.
For a 6-band example, brown, black, black, red, brown, brown reads 100 × 100 = 10 kΩ ±1% with a temperature coefficient of 100 ppm/K.
E12 and E24 standard values
Resistors are not made in every value. Manufacturers use the preferred-number series in IEC 60063. Within each 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) and E24 adds 12 more (1.1, 1.3, 1.6, 2.0, 2.4, 3.0, 3.6, 4.3, 5.1, 6.2, 7.5, 9.1). The steps are spaced so that the ±10% (E12) or ±5% (E24) tolerance bands of neighboring values roughly meet. That is why the reverse lookup picks the nearest standard value: it is the one you can actually buy.
Common mistakes
- Reading the code backwards. Brown, black, orange, gold is 10 kΩ, but read from the wrong end you would try to decode a gold first digit, which doesn't exist. If neither end is gold or silver, look for the wider gap before the last band.
- Confusing similar colors. Brown, red and orange, and violet and grey, look alike under warm or dim light. If the result is not a standard E-series value, suspect a misread color.
- Treating a 5-band part as 4-band. On a 5-band precision resistor the third band is a digit, not the multiplier. Brown, black, black, red, brown is 10 kΩ ±1%, not 1 kΩ.
- Trusting old grey bands. Some older parts used grey to mean ±0.05%, and some high-voltage resistors used yellow or grey in place of gold or silver. When it matters, measure the part.
- Measuring in circuit. A multimeter reading taken with the resistor still soldered in also measures everything in parallel with it.
Use cases
- Sorting a bag of loose through-hole resistors from a kit or salvage.
- Checking that the part going into a board matches the schematic before soldering.
- Finding the standard value and bands closest to a calculated value, for example from an LED resistor calculation or the Ohm's Law Calculator.
- Printing the chart for a workbench, classroom or electronics club.
To check how far a measured value is from nominal as a percentage, the Percentage Calculator does the math.
Frequently asked questions
A 3-band resistor has two digit bands and a multiplier, and no tolerance band. Missing tolerance means ±20%. Red, red, orange, for example, is 22 × 1,000 = 22 kΩ ±20%. In this calculator, choose 4 bands and set the last band to None.
On a 4-band resistor, 10 kΩ is brown, black, orange, followed by the tolerance band, usually gold for ±5%. On a 5-band precision resistor it is brown, black, black, red, followed by a tolerance band such as brown for ±1%.
A 4-band 220 Ω resistor is red, red, brown plus a tolerance band, often gold. That reads 22 × 10 = 220 Ω. The 5-band version is red, red, black, black, with brown commonly used for ±1% tolerance.
Yes. Gold as the multiplier means ×0.1 and silver means ×0.01. Yellow, violet, gold, gold is 47 × 0.1 = 4.7 Ω ±5%, and brown, black, silver is 10 × 0.01 = 0.1 Ω. The IEC 60062:2016 table also lists pink for ×0.001, which this calculator does not include.
It stands for parts per million per kelvin, the temperature coefficient of resistance. A 10 kΩ resistor rated 100 ppm/K can change by up to 1 Ω for each degree Celsius of temperature change, which adds up to 50 Ω over a 50 °C swing.
Use a multimeter on its resistance range with the resistor out of the circuit, and avoid touching both leads with your fingers, since your body adds a parallel path. The reading should fall inside the tolerance range shown by this calculator.