Complete Resistor Calculator Guide
Our comprehensive resistor calculator helps you calculate resistor values using color codes, series/parallel combinations, power dissipation, and voltage division. Whether you're working with 4-band, 5-band, or 6-band resistors, this tool provides accurate calculations for all your electronic projects.
Resistor Color Code Calculator
The resistor color code calculator helps you decode the colored bands on resistors to determine their resistance value and tolerance. Our calculator supports:
- 4-Band Resistors: 2 digits + multiplier + tolerance
- 5-Band Resistors: 3 digits + multiplier + tolerance
- 6-Band Resistors: 3 digits + multiplier + tolerance + temperature coefficient
Resistor Color Code Chart
| Color |
Digit |
Multiplier |
Tolerance |
| Black | 0 | ×1 | - |
| Brown | 1 | ×10 | ±1% |
| Red | 2 | ×100 | ±2% |
| Orange | 3 | ×1K | - |
| Yellow | 4 | ×10K | - |
| Green | 5 | ×100K | ±0.5% |
| Blue | 6 | ×1M | ±0.25% |
| Violet | 7 | ×10M | ±0.1% |
| Grey | 8 | - | - |
| White | 9 | - | - |
| Gold | - | ×0.1 | ±5% |
| Silver | - | ×0.01 | ±10% |
Series and Parallel Resistor Calculator
Calculate the total resistance of resistors connected in series or parallel:
- Series Resistance: Rtotal = R₁ + R₂ + R₃ + ... + Rₙ
- Parallel Resistance: 1/Rtotal = 1/R₁ + 1/R₂ + 1/R₃ + ... + 1/Rₙ
Resistor Power Calculator
Calculate power dissipation in resistors using these formulas:
- P = V²/R (Power = Voltage squared / Resistance)
- P = I²R (Power = Current squared × Resistance)
- P = VI (Power = Voltage × Current)
Voltage Divider Calculator
Calculate output voltage in voltage divider circuits:
- Vout = Vin × R₂ / (R₁ + R₂)
- Used in sensor circuits, reference voltages, and signal conditioning
Standard Resistor Values (E-Series)
Common resistor values follow E-series standards:
- E12 Series (±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 Series (±5%): All E12 values plus 1.1, 1.3, 1.6, 2.0, 2.4, 3.0, 3.6, 4.3, 5.1, 6.2, 7.5, 9.1
- E96 Series (±1%): 96 standard values for precision applications
Resistor Applications and Types
- Current Limiting: Protect LEDs and other components
- Pull-up/Pull-down: Define logic levels in digital circuits
- Voltage Division: Create reference voltages
- Timing Circuits: RC time constants
- Filtering: Low-pass and high-pass filters
Resistor Types and Materials
- Carbon Film: General purpose, ±5% tolerance
- Metal Film: Higher precision, ±1% tolerance
- Carbon Composition: Vintage, high pulse capability
- Wire Wound: High power, precision applications
- Surface Mount (SMD): Compact designs, automated assembly
Power Rating and Heat Dissipation
Choose appropriate power ratings for your applications:
- 1/8W (0.125W): Small signal applications
- 1/4W (0.25W): General purpose circuits
- 1/2W (0.5W): Medium power applications
- 1W and above: High power circuits, may require heat sinking
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