A resistor color code calculator decodes the colored bands printed on through-hole resistors to determine their resistance value and tolerance. Whether you are prototyping on a breadboard or repairing a circuit board, this tool helps you quickly identify any 4-band, 5-band, or 6-band resistor without memorizing the entire color chart.
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Resistor Color Code Chart
| Color | Digit | Multiplier | Tolerance | Temp Coeff |
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How to Use the Resistor Color Code Calculator
Through-hole resistors use colored bands to encode their resistance value, tolerance, and sometimes temperature coefficient. Memorizing every combination is impractical, especially for occasional electronics work. This resistor color code calculator decodes the bands instantly and even works in reverse when you need to find a specific resistor.
Step 1: Choose the Number of Bands
Select whether your resistor has 4, 5, or 6 colored bands. Most common resistors have 4 bands, while precision resistors typically have 5 bands. Six-band resistors add a temperature coefficient rating. If you are unsure, count the bands visible on the component and match it to the selector.
Step 2: Select Colors for Each Band
Use the dropdown menus to choose the color for each band, starting from the band closest to one end of the resistor. The SVG diagram updates in real time to show your selections. The first two or three bands represent significant digits, the next band is the multiplier (number of zeros), and the last band is the tolerance rating.
Step 3: Read the Result
The calculator displays the decoded resistance value formatted in ohms, kilohms, or megohms as appropriate. It also shows the tolerance percentage and the minimum and maximum values based on that tolerance range. For 6-band resistors, the temperature coefficient in ppm/C is displayed as well.
Step 4: Use Reverse Lookup
Switch to "Value to Color" mode to find which color bands correspond to a known resistance. Enter the value, select the unit, pick a tolerance rating, and click Lookup. The tool calculates the correct band colors and displays them on the visual resistor. This is especially useful when sorting through a bin of resistors or designing a circuit from a schematic.
Understanding the Color Code System
The resistor color code system assigns each color a digit from 0 (Black) to 9 (White). The multiplier band uses the same colors but represents powers of ten, plus Gold (0.1) and Silver (0.01) for sub-ohm values. Tolerance bands use a subset of colors: Gold for the common 5%, Brown for 1%, and rarer colors for higher precision. Open the reference chart below the calculator for a complete breakdown of all color assignments.
FAQ
Is this resistor color code calculator free?
Yes, this resistor color code calculator is completely free with no limits. Decode as many resistors as you need without creating an account or paying anything.
Is my data safe when using this tool?
Absolutely. All calculations run entirely in your browser using JavaScript. No data is ever sent to any server. The tool works completely offline once the page loads.
How do I read a 4-band resistor?
On a 4-band resistor, the first two bands represent significant digits, the third band is the multiplier, and the fourth band indicates tolerance. For example, Brown-Black-Red-Gold means 1-0 x 100 = 1000 ohms (1k) with plus or minus 5% tolerance.
What is the difference between 4-band and 5-band resistors?
A 5-band resistor has three significant digits instead of two, giving higher precision. The first three bands are digits, the fourth is the multiplier, and the fifth is tolerance. Five-band resistors are common in precision circuits requiring 1% or better tolerance.
What does the 6th band on a resistor mean?
The sixth band indicates the temperature coefficient in parts per million per degree Celsius (ppm/C). It tells you how much the resistance changes with temperature. Common values are 100 ppm/C (Brown) for standard resistors and 10 ppm/C (Blue) for high-stability types.
What do Gold and Silver bands mean on a resistor?
Gold and Silver can appear as either a multiplier or tolerance band. As a multiplier, Gold means multiply by 0.1 and Silver means multiply by 0.01. As tolerance, Gold means plus or minus 5% and Silver means plus or minus 10%.
How do I find resistor colors from a known resistance value?
Use the Reverse Lookup mode in this calculator. Enter your target resistance value in ohms and select the number of bands. The tool will determine the correct color sequence and display it visually on the resistor diagram.
Which end of the resistor do I start reading from?
Start from the end where the bands are closer together or where the first band is nearest the edge. The tolerance band (often Gold or Silver) is usually slightly separated from the other bands and positioned at the opposite end.