Resistor Color Code
Resistor bands encode value: 1st–2nd (3rd for 5-band) = digits; multiplier; tolerance. EIA RS-279 / IEC 60062.
Why This Physics Calculation Matters
Why: Color codes are the standard for through-hole resistors. Essential for circuit building, repair, and education.
How: Read digits left to right; multiplier sets scale (Ω, kΩ, MΩ); tolerance band last. 5-band adds digit for precision.
- ●Black=0, Brown=1, Red=2, Orange=3, Yellow=4, Green=5, Blue=6, Violet=7, Gray=8, White=9.
- ●Multiplier: Black=1, Brown=10, Red=100, Orange=1k, Yellow=10k, Green=100k, Blue=1M.
- ●Gold tolerance ±5%, Silver ±10% common; Brown ±1%, Red ±2% for precision.
- ●5-band: first 3 = digits; 4th = multiplier; 5th = tolerance.
Sample Examples
Click a scenario to load example color band values:
1 kΩ (4-Band)
Brown-Black-Red-Gold
Click to use
10 kΩ (4-Band)
Brown-Black-Orange-Gold
Click to use
100 kΩ (4-Band)
Brown-Black-Yellow-Gold
Click to use
1 kΩ (5-Band)
Brown-Black-Black-Brown-Brown
Click to use
47 kΩ (4-Band)
Yellow-Violet-Orange-Gold
Click to use
220 Ω (4-Band)
Red-Red-Brown-Gold
Click to use
Resistor Configuration
Band Type
Visual Preview
Color Bands
RESISTANCE CALCULATION
Color code to resistance value
nominal value
accuracy
lowest value
highest value
Calculation Steps
Step 1: Identify significant digits from color bands
Band 1: brown = 1, Band 2: black = 0
Step 2: Combine significant digits
Base value = 1 × 10 + 0 = 10
Step 3: Apply multiplier
Multiplier: brown = ×10
Resistance = 10 × 10 = 100 Ω
Step 4: Calculate tolerance range
Tolerance: gold = ±5%
Range: 95.00 Ω to 105.00 Ω
⚠️For educational and informational purposes only. Verify with a qualified professional.
🔬 Physics Facts
EIA RS-279 and IEC 60062 define standard color codes.
— EIA
5-band: 3 digits for 1% or better tolerance resistors.
— IEC
Tolerance band often gold or silver; wider spacing before it.
— Electronics
Brown-black-red = 10×100 = 1 kΩ (4-band).
— Circuit design
🔑 Key Takeaways
- •4-band resistors: First two bands are significant digits, third is multiplier, fourth is tolerance
- •5-band resistors: First three bands are significant digits, fourth is multiplier, fifth is tolerance
- •6-band resistors: Add temperature coefficient band after tolerance
- •Tolerance bands: Gold = ±5%, Silver = ±10%, Brown = ±1%, Red = ±2%
- •Memory aid: "BB ROY GB VGW" (Bad Beer Rots Our Young Guts But Vodka Goes Well) for color sequence
💡 Did You Know?
1920s Color Code Origin
The resistor color code was developed in the 1920s by the Radio Manufacturers Association (RMA) for vacuum tube era electronics
0Ω Resistor = Jumper Wire
A zero-ohm resistor (single black band) is actually a jumper wire in resistor package form, used for automated PCB assembly
Gold Tolerance = 5%
Gold band indicates ±5% tolerance, the most common tolerance for general-purpose resistors
E-Series Preferred Values
Resistors are manufactured in E-series values (E12, E24, E96) following geometric progression for even spacing
SMD Uses Different Codes
Surface mount resistors use numeric codes (3-digit, 4-digit, EIA-96) instead of color bands due to small size
Carbon vs Metal Film
Carbon film resistors have ±5% tolerance, while metal film offers ±1% or better with lower noise
🔧 How It Works
Reading Color Bands
4-Band System
- 1First band: First significant digit (0-9)
- 2Second band: Second significant digit (0-9)
- 3Third band: Multiplier (power of 10)
- 4Fourth band: Tolerance percentage
5-Band System
- 1First three bands: Three significant digits
- 2Fourth band: Multiplier (power of 10)
- 3Fifth band: Tolerance percentage
- 4Sixth band (optional): Temperature coefficient
🎯 Expert Tips
Read from Left to Right
Start reading from the band closest to one end. The tolerance band (gold/silver/none) is always at the opposite end, helping you identify the starting point.
Use Mnemonic Devices
Remember "BB ROY GB VGW" (Bad Beer Rots Our Young Guts But Vodka Goes Well) for the color sequence: Black, Brown, Red, Orange, Yellow, Green, Blue, Violet, Grey, White.
Check Tolerance Bands
Gold (±5%) and Silver (±10%) are common tolerance bands. Brown (±1%) and Red (±2%) indicate precision resistors. None indicates ±20% tolerance.
Verify with Multimeter
Always verify resistor values with a multimeter, especially for critical circuits. Color bands can fade or be misread, and resistors can drift over time.
📊 Resistor Coding Systems Comparison
| Type | Bands | Precision | Common Use |
|---|---|---|---|
| 4-Band | 2 digits + multiplier + tolerance | ±5% to ±20% | General purpose circuits |
| 5-Band | 3 digits + multiplier + tolerance | ±1% to ±5% | Precision circuits |
| 6-Band | 3 digits + multiplier + tolerance + TCR | ±0.5% to ±1% | High precision applications |
| SMD | Numeric codes (3/4-digit or EIA-96) | ±1% to ±5% | Surface mount technology |
❓ Frequently Asked Questions
Q: Which direction do I read the color bands?
Start from the band closest to one end of the resistor. The tolerance band (gold, silver, or none) is always at the opposite end. In 4-band resistors, there's usually a wider gap before the tolerance band.
Q: Why can't I find my calculated resistance in standard values?
Resistors come only in E-series standard values. Use the closest standard value, or combine resistors in series or parallel to achieve non-standard values. For critical applications, use trimmer potentiometers for fine adjustment.
Q: What's the difference between 4-band and 5-band resistors?
4-band resistors have 2 significant digits and are used for general purposes (±5% tolerance). 5-band resistors have 3 significant digits for higher precision (±1% tolerance) and are used in precision circuits.
Q: Can I replace a 5% resistor with a 1% resistor?
Yes, using a tighter tolerance is always acceptable and may improve circuit performance. However, 1% resistors are more expensive and may have different characteristics (noise, TCR), so it may be overkill for non-critical applications.
Q: How do I read a 6-band resistor?
Six-band resistors add a temperature coefficient band after the tolerance band. Bands 1-3 are significant digits, band 4 is multiplier, band 5 is tolerance, and band 6 indicates TCR (often brown for ±100ppm/°C or red for ±50ppm/°C).
Q: What does "zero-ohm" resistor mean?
A zero-ohm resistor is actually a jumper wire in resistor package form. It has a single black band and near-zero resistance. Used in PCB manufacturing where automated placement is standard but a wire jumper is needed.
Q: What is a fusible resistor?
A fusible resistor acts as both a resistor and a fuse. It opens (like a fuse) when current exceeds its rating, protecting the circuit. Often used in power supplies. Marked with special coloring or designation.
Q: How do SMD resistors differ from through-hole resistors?
Surface mount (SMD) resistors use numeric codes instead of color bands due to their small size. Common systems include 3-digit (e.g., "104" = 100kΩ), 4-digit (e.g., "1002" = 10kΩ), and EIA-96 codes (e.g., "01Y" = 1.00Ω).
📈 Infographic Stats
📚 Official Data Sources
⚠️ Disclaimer: This calculator provides estimates based on standard resistor color coding systems (IEC 60062, EIA RS-279). Actual resistor values may vary due to manufacturing tolerances, temperature effects, aging, and component quality. Always verify resistor values with a calibrated multimeter for critical applications. Color bands can fade, be misread, or vary between manufacturers. Consult manufacturer datasheets for specific resistor characteristics, power ratings, temperature coefficients, and specifications. This calculator is for educational and reference purposes. For professional circuit design, consider component tolerances, temperature effects, power dissipation, and use appropriate safety margins.