Resistor Color Code Calculator
Quickly find resistor values from color bands or convert values back to colors. Includes tolerance and temperature coefficient calculations.
Resistor Visualization
Results
Color Code Reference
Tolerance Values
Standard Values (E-Series):
- • E12 (10%): 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 (5%): E12 + 1.1, 1.3, 1.6, 2.0, 2.4, 3.0, 3.6, 4.3, 5.1, 6.2, 7.5, 9.1
- • Values repeat in decades (10Ω, 100Ω, 1kΩ, 10kΩ, etc.)
Understanding Resistor Color Codes
Resistor color codes are a standardized method for indicating the resistance value, tolerance, and sometimes temperature coefficient of resistors. Since resistors are often too small to print numerical values, colored bands provide a universal way to identify their specifications. This system has been used since the 1920s and remains the industry standard.
How to Read Resistor Color Bands
Resistors come with 3, 4, 5, or 6 color bands. Here's how to decode them:
- 4-Band Resistors: Most common type with two significant digits, multiplier, and tolerance
- 5-Band Resistors: Precision resistors with three significant digits, multiplier, and tolerance
- 6-Band Resistors: High-precision resistors including temperature coefficient
Standard Color Code Chart
Each color represents a specific digit or multiplier:
- Black = 0, Brown = 1, Red = 2
- Orange = 3, Yellow = 4, Green = 5
- Blue = 6, Violet = 7, Gray = 8, White = 9
- Gold = ×0.1, Silver = ×0.01
Tolerance Values
The tolerance band indicates how much the actual resistance can vary from the marked value:
- Brown = ±1% (precision)
- Red = ±2% (precision)
- Gold = ±5% (standard)
- Silver = ±10% (general purpose)
- No band = ±20% (low precision)
How to Use This Calculator
- Color to Value: Select the band colors from dropdowns to get the resistance value
- Value to Color: Enter a resistance value to see the corresponding color bands
- Choose the number of bands (4, 5, or 6) based on your resistor type
- View the tolerance and temperature coefficient if applicable
Example Calculations
Example 1: 4-Band Resistor
Colors: Red, Violet, Orange, Gold
Reading: 2, 7, ×1000Ω, ±5%
Value: 27,000Ω or 27kΩ ±5%
Example 2: 5-Band Resistor
Colors: Brown, Black, Black, Red, Brown
Reading: 1, 0, 0, ×100Ω, ±1%
Value: 10,000Ω or 10kΩ ±1%
Common Resistor Values (E-Series)
Standard resistor values follow E-series (E6, E12, E24, E96) which ensures geometric spacing. Common values include: 10Ω, 22Ω, 47Ω, 100Ω, 220Ω, 470Ω, 1kΩ, 2.2kΩ, 4.7kΩ, 10kΩ, 22kΩ, 47kΩ, 100kΩ, 220kΩ, 470kΩ, and 1MΩ.
Tips for Reading Resistors
- The tolerance band (usually gold or silver) is typically more separated and helps identify which end to start reading from
- Hold the resistor so the tolerance band is on the right
- Use a multimeter to verify the value if uncertain
- In good lighting conditions, brown and violet can look similar - double check
Frequently Asked Questions
Q: Which end of the resistor do I read first?
A: Start from the end closest to a band, or where the tolerance band (gold/silver) is on the opposite end. The first band is never gold or silver.
Q: What if my resistor has 3 bands?
A: 3-band resistors are older and have two significant digits plus a multiplier, with ±20% tolerance assumed.
Q: Can I use any resistor value in my circuit?
A: You should use standard E-series values when possible. For specific values, you can combine resistors in series or parallel.
Q: Why do precision resistors have more bands?
A: Additional bands allow for more significant digits (better precision) and can include temperature coefficient information for high-stability applications.