Decode resistor color bands
Choose four, five, or six bands. The result appears above this form.
Find a common four-band sequence
Enter a nominal value to find the nearest standard sequence with your chosen tolerance.
Resistor color code chart
Digits form the base value. The multiplier scales it. Tolerance defines the allowed production variation.
| Color | Digit | Multiplier | Tolerance | Temperature coefficient |
|---|---|---|---|---|
| Black | 0 | ×1 | — | — |
| Brown | 1 | ×10 | ±1% | 100 ppm/°C |
| Red | 2 | ×100 | ±2% | 50 ppm/°C |
| Orange | 3 | ×1 k | — | 15 ppm/°C |
| Yellow | 4 | ×10 k | — | 25 ppm/°C |
| Green | 5 | ×100 k | ±0.5% | — |
| Blue | 6 | ×1 M | ±0.25% | 10 ppm/°C |
| Violet | 7 | ×10 M | ±0.1% | 5 ppm/°C |
| Grey | 8 | ×100 M | ±0.05% | — |
| White | 9 | ×1 G | — | — |
| Gold | — | ×0.1 | ±5% | — |
| Silver | — | ×0.01 | ±10% | — |
| None | — | — | ±20% | — |
Example data table
| Band sequence | Band count | Nominal value | Tolerance | Allowed range |
|---|---|---|---|---|
| Yellow, Violet, Red, Gold | 4 | 4.7 kΩ | ±5% | 4.465 kΩ to 4.935 kΩ |
| Brown, Black, Black, Red, Brown | 5 | 10 kΩ | ±1% | 9.9 kΩ to 10.1 kΩ |
| Blue, Grey, Black, Brown, Violet, Red | 6 | 6.8 kΩ | ±0.1% | 6.7932 kΩ to 6.8068 kΩ |
Formula used
The calculator combines significant digits, then applies the multiplier and tolerance.
For six-band resistors, the final band gives the temperature coefficient. It estimates how resistance can change with temperature.
How to use this calculator
- Set the number of colored bands on the resistor.
- Choose each band from left to right.
- Add quantity and power rating when useful.
- Press calculate to display value, limits, and details.
- Download CSV or PDF after a successful calculation.
- Use reverse lookup when you know the target resistance.
Reading resistor colors accurately
Resistors control current and divide voltage in electronic circuits. A color code labels their value without printing numbers. This system remains useful on small parts, where ordinary text would be difficult to read. Each colored band represents a digit, multiplier, tolerance, or temperature coefficient. Reading the bands correctly helps you choose replacements, diagnose faults, and protect components from excess current.
Read a fixed resistor from the end with the grouped bands. A tolerance band often sits farther from the other bands. For a four-band resistor, the first two bands create the significant number. The third band is the multiplier. The final band gives tolerance. A five-band resistor uses three significant digits. A six-band resistor adds a temperature coefficient band, usually measured in parts per million per degree Celsius.
The multiplier changes a simple number into an electrical resistance value. For example, red, violet, and orange means 27 multiplied by one thousand. The nominal resistance is therefore 27 kilo-ohms. A gold tolerance band allows a five percent variation. That resistor may measure between 25.65 kilo-ohms and 28.35 kilo-ohms under normal conditions. A meter reading inside that range can still be correct.
Tolerance matters when circuit accuracy is important. Timing networks, sensor circuits, filters, and voltage dividers may require one percent or lower tolerance. General indicator circuits often accept five percent parts. Temperature coefficient matters in changing environments. A lower coefficient means the resistance changes less when the part becomes hot or cold. This can improve long-term measurement stability.
Use this calculator to decode a selected band sequence and check the permitted range. You can also enter a target resistance for a reverse lookup. Compare the result with the component label, schematic, and measured value. Confirm the wattage separately, because color bands usually do not state power rating. Never assume resistance alone makes a replacement safe. Check voltage, current, package size, heat, and circuit purpose before installation. Accurate decoding saves time and reduces avoidable troubleshooting errors.
Keep leads isolated while testing resistance in-circuit. Parallel paths can produce misleading readings. Remove one lead where practical, then measure with power disconnected. Record the measured result, rating, and tolerance for future servicing. This creates a useful maintenance trail and prevents repeat identification work later. It improves consistency across teams, benches, and repair records.
Frequently asked questions
1. Which end of a resistor should I read first?
Start at the end where colored bands sit closer together. The tolerance band is often separated by a wider gap. Gold, silver, or an absent tolerance band usually appears last.
2. What does a four-band resistor show?
It shows two significant digits, one multiplier, and one tolerance band. This arrangement is common for general-purpose carbon film and metal film resistors.
3. What does a five-band resistor show?
It shows three significant digits, a multiplier, and tolerance. Five-band markings are common where a more precise nominal value is needed.
4. Why does a six-band resistor include another color?
The sixth band provides the temperature coefficient. It indicates how much the resistance may change for each degree Celsius of temperature change.
5. What does a gold multiplier mean?
Gold as a multiplier means multiply the significant digits by 0.1. Gold commonly appears as a tolerance band too, where it means plus or minus five percent.
6. Can I use a different tolerance resistor?
Often yes, when the replacement tolerance is equal or tighter. Check the schematic, intended accuracy, voltage, power, size, temperature conditions, and required reliability first.
7. Why is my measured value not exact?
Manufacturing tolerance, temperature, meter accuracy, lead contact, and parallel circuit paths can affect a reading. Compare the measurement with the calculated tolerance range.
8. Does the color code state wattage?
Usually no. Determine wattage from the resistor body size, product markings, datasheet, or circuit documentation. A correct resistance value can still fail if wattage is too low.
9. What is the difference between grey and silver?
Grey is a digit color with value eight. Silver is not a significant digit. Silver is used for a 0.01 multiplier or a plus or minus ten percent tolerance.
10. Can this calculator decode surface-mount resistors?
No. Surface-mount resistors usually use numeric, EIA-96, or manufacturer-specific markings. Use the component marking and package documentation instead.
11. Is resistance safe to measure in a powered circuit?
No. Disconnect power and discharge capacitors before measuring resistance. Measuring a powered circuit can damage your meter, create inaccurate results, or cause injury.