Loading...
Free resistor calculator: Decode color codes, calculate resistance values, find color bands for any resistance. Supports 4, 5, 6-band resistors with tolerance and temperature coefficient calculations.
This resistor color code calculator is designed and maintained by electronics engineers following the IEC 60062 international standard for resistor marking. Our calculator provides accurate, instant results for decoding resistor color bands and finding color codes for specific resistance values.
Why trust this calculator? All calculations are based on industry-standard formulas and verified against manufacturer datasheets from leading resistor manufacturers including Vishay, Yageo, and Bourns. The tool supports all common resistor types (4-band, 5-band, and 6-band) and includes E12, E24, and E96 series standard values.
Educational Purpose: Beyond calculations, this page provides comprehensive educational content about resistor color codes, tolerance, temperature coefficients, and practical applications. All information is sourced from authoritative electronics standards and manufacturer specifications.
Resistor color codes are a standardized system for marking the resistance value, tolerance, and sometimes temperature coefficient on resistors. Since resistors are small components, colored bands are used instead of printed numbers. This system was developed in the 1920s and is still widely used today.
Reading Direction:
Always read resistors from left to right. The tolerance band (usually gold or silver) is typically on the right side and is slightly separated from the other bands.
Most common type for general-purpose resistors:
Example: Brown-Black-Red-Gold
1 (Brown) + 0 (Black) × 100 (Red) = 1000Ω = 1kΩ ±5% (Gold)
Used for precision resistors (±1% or better):
Example: Brown-Black-Black-Brown-Brown
1 (Brown) + 0 (Black) + 0 (Black) × 10 (Brown) = 1000Ω = 1kΩ ±1% (Brown)
High-precision resistors with temperature coefficient:
Temperature Coefficient: Indicates how much the resistance changes per degree Celsius. Lower ppm values mean better stability across temperature changes.
| Color | Visual | Digit Value | Multiplier | Tolerance | Temp Coeff |
|---|---|---|---|---|---|
| Black | 0 | ×1 | - | - | |
| Brown | 1 | ×10 | ±1% | 100ppm | |
| Red | 2 | ×100 | ±2% | 50ppm | |
| Orange | 3 | ×1K | - | 15ppm | |
| Yellow | 4 | ×10K | - | 25ppm | |
| Green | 5 | ×100K | ±0.5% | - | |
| Blue | 6 | ×1M | ±0.25% | 10ppm | |
| Violet | 7 | ×10M | ±0.1% | 5ppm | |
| Gray | 8 | ×100M | ±0.05% | - | |
| White | 9 | - | - | - | |
| Gold | - | ×0.1 | ±5% | - | |
| Silver | - | ×0.01 | ±10% | - |
12 values per decade, most common for general-purpose resistors:
These values repeat for each decade: 1Ω-10Ω, 10Ω-100Ω, 100Ω-1kΩ, 1kΩ-10kΩ, etc.
24 values per decade, used for more precise applications:
96 values per decade, for precision applications. Includes all E24 values plus many more intermediate values.
E96 series provides very fine resolution with values like 100, 102, 105, 107, 110, 113, 115, 118, 121, 124, 127, 130, etc.
Scenario: 5V supply, 20mA LED, 2V forward voltage
Calculation: R = (5V - 2V) / 0.02A = 150Ω
Color Code: Brown-Green-Brown-Gold
✓ Use 150Ω ±5% resistor
Scenario: I2C bus, 3.3V logic, typical value
Standard Value: 4.7kΩ (4700Ω)
Color Code: Yellow-Violet-Red-Gold
✓ Use 4.7kΩ ±5% resistor
Scenario: 12V to 5V divider, R1 = 10kΩ
Calculation: R2 = 10k × 5/(12-5) = 7.14kΩ
Closest Standard: 6.8kΩ or 7.5kΩ
✓ Use 6.8kΩ (Blue-Gray-Red-Gold)
Scenario: BJT transistor, 5V input, 1mA base current
Calculation: R = (5V - 0.7V) / 0.001A = 4.3kΩ
Closest Standard: 4.7kΩ
✓ Use 4.7kΩ (Yellow-Violet-Red-Gold)
Read resistor color codes from left to right. For 4-band resistors: first two bands are digits, third is multiplier, fourth is tolerance. For 5-band: first three are digits, fourth is multiplier, fifth is tolerance. Each color represents a number: Black=0, Brown=1, Red=2, Orange=3, Yellow=4, Green=5, Blue=6, Violet=7, Gray=8, White=9.
A 1k ohm (1000Ω) resistor has the color code: Brown-Black-Red-Gold. Brown (1), Black (0), Red (×100 multiplier) = 10 × 100 = 1000Ω = 1kΩ. Gold band indicates ±5% tolerance.
4-band resistors provide 2 significant digits with typical tolerances of ±5% or ±10%, suitable for general-purpose applications. 5-band resistors provide 3 significant digits with tighter tolerances of ±1% or ±2%, offering higher precision for applications requiring accurate resistance values such as precision amplifiers and measurement circuits.
Calculate voltage, current, resistance, power
Wire sizing and voltage drop calculations
Power consumption and cost calculator
Unit conversions for electrical values
Advanced mathematical calculations
Calculate percentages and ratios