Resistor Color Band Reader
Select the number of bands and the color of each one. The result updates instantly with the nominal value and tolerance.
Result--
Free tool
Resistor calculator and color code reader
Use this resistor calculator to read the color code and get the value in ohms quickly. If you came here looking for a resistor calculator, a resistor reader or a tool for resistor calculations, you can do it here clearly and without complications.
Tools
Color Code Reader and Resistor Calculations
Use the tool as an online resistor reader to identify 4-band or 5-band resistors and also calculate equivalent values when you work with several resistors in series or in parallel.
Resistors in Seriess and Parallel
Enter several values in ohms separated by commas, spaces or line breaks and get the equivalent resistance without leaving the page.
Equivalent1.02 kΩ
Quick tip
If you mix different units, convert them to ohms first. The parallel calculation uses the inverse expression and is especially useful when you are adjusting standard values.
Quick guide
How to Read a Resistor Color Code
Resistors are identified by color bands. Each band represents a numeric value, a multiplier or a tolerance. In 4-band resistors, the first two bands indicate the digits, the third the multiplier and the fourth the tolerance. In 5-band resistors, the first three bands indicate the significant digits, the fourth the multiplier and the fifth the tolerance.
- 4 bands: digit, digit, multiplier and tolerance
- 5 bands: digit, digit, digit, multiplier and tolerance
- The tolerance band is usually separated from the rest
- Gold and silver usually indicate small multipliers or tolerance values
Resistor Calculation Examples
- Brown - Black - Red - Gold = 1.000 Ω ±5%
- Red - Red - Brown - Gold = 220 Ω ±5%
- Yellow - Violet - Brown - Gold = 470 Ω ±5%
- Yellow - Violet - Black - Black - Brown = 470 Ω ±1%
These examples help you use the calculator as a resistor reader and quickly check whether you are interpreting the color code correctly.
Quick Resistor Color Table
| Color | Digit | Multiplier | Tolerance |
|---|---|---|---|
| Black | 0 | x1 | — |
| Brown | 1 | x10 | ±1% |
| Red | 2 | x100 | ±2% |
| Orange | 3 | x1,000 | — |
| Yellow | 4 | x10,000 | — |
| Green | 5 | x100,000 | ±0.5% |
| Blue | 6 | x1,000.000 | ±0.25% |
| Violet | 7 | x10,000.000 | ±0.1% |
| Grey | 8 | x100,000.000 | ±0.05% |
| White | 9 | x1,000.000.000 | — |
| Gold | — | x0.1 | ±5% |
| Silver | — | x0.01 | ±10% |
Related
Other Calculators and Related Resources
FAQ
Frequently asked questions about resistors
How do you know the value of a resistor from its colors?
You need to read the bands from left to right and identify digits, multiplier and tolerance. This calculator does that automatically when you select the colors.
What does the gold or silver band mean?
It usually indicates tolerance or a small multiplier. Gold often represents ±5% or x0.1 and silver ±10% or x0.01.
What is the difference between 4-band and 5-band resistors?
4-band resistors use two significant digits, while 5-band resistors use three, which allows a more precise reading.
Can this calculator be used as a resistor reader?
Yes. You can use it as an online resistor reader to quickly identify the value in ohms from the color code.
Next step
If you need more than electronics calculations and want professional help developing a device or prototype, you can visit our service page or contact RobotUNO.