Resistor Calculator
Calculate resistor values, color codes, and combinations (series and parallel). This tool helps you decode information for color banded axial lead resistors, determine resistance values from color codes, and calculate equivalent resistance for series or parallel circuits.
Calculation Results
Resistance: -
Tolerance: -
Temperature Coefficient: -
Standard Resistor Values (E12 Series)
| Value | Multipliers |
|---|---|
| 1.0 | 10, 100, 1k, 10k, 100k, 1M |
| 1.2 | 12, 120, 1.2k, 12k, 120k, 1.2M |
| 1.5 | 15, 150, 1.5k, 15k, 150k, 1.5M |
| 1.8 | 18, 180, 1.8k, 18k, 180k, 1.8M |
| 2.2 | 22, 220, 2.2k, 22k, 220k, 2.2M |
| 2.7 | 27, 270, 2.7k, 27k, 270k, 2.7M |
| 3.3 | 33, 330, 3.3k, 33k, 330k, 3.3M |
| 3.9 | 39, 390, 3.9k, 39k, 390k, 3.9M |
| 4.7 | 47, 470, 4.7k, 47k, 470k, 4.7M |
| 5.6 | 56, 560, 5.6k, 56k, 560k, 5.6M |
| 6.8 | 68, 680, 6.8k, 68k, 680k, 6.8M |
| 8.2 | 82, 820, 8.2k, 82k, 820k, 8.2M |
About the Resistor Calculator
Our resistor calculator is a comprehensive tool designed to help you work with resistors in electronic circuits. It provides three main functions: decoding resistor color codes, calculating resistance values from color bands, and determining equivalent resistance for series and parallel combinations.
How to Use the Calculator
- Color Code Tab: Select the number of bands, then click on each band to choose its color. The calculator will display the resistance value, tolerance, and temperature coefficient.
- Resistance Tab: Enter a resistance value and select the unit (Ω, kΩ, MΩ). Choose the tolerance and number of bands to see the corresponding color code.
- Series/Parallel Tab: Select the circuit type (series or parallel), enter the number of resistors, then input each resistor's value. The calculator will compute the total equivalent resistance.
Resistor Color Code System
The resistor color code is a standard method for indicating the value and tolerance of resistors. The system uses colored bands to represent numbers and multipliers:
| Color | Digit | Multiplier | Tolerance | Temp. Coefficient |
|---|---|---|---|---|
| Black | 0 | 100 | - | 250 ppm/°C |
| Brown | 1 | 101 | ±1% | 100 ppm/°C |
| Red | 2 | 102 | ±2% | 50 ppm/°C |
| Orange | 3 | 103 | ±0.05% | 15 ppm/°C |
| Yellow | 4 | 104 | ±0.02% | 25 ppm/°C |
| Green | 5 | 105 | ±0.5% | 20 ppm/°C |
| Blue | 6 | 106 | ±0.25% | 10 ppm/°C |
| Violet | 7 | 107 | ±0.1% | 5 ppm/°C |
| Gray | 8 | 108 | ±0.01% | 1 ppm/°C |
| White | 9 | 109 | - | - |
| Gold | - | 10-1 | ±5% | - |
| Silver | - | 10-2 | ±10% | - |
Series and Parallel Resistor Calculations
Resistors in electronic circuits can be connected in series or parallel configurations:
Series Connection:
When resistors are connected in series, the total resistance is the sum of all individual resistances:
Rtotal = R1 + R2 + R3 + ... + Rn
Parallel Connection:
When resistors are connected in parallel, the reciprocal of the total resistance is equal to the sum of the reciprocals of each resistance:
1/Rtotal = 1/R1 + 1/R2 + 1/R3 + ... + 1/Rn
For two resistors in parallel, the formula simplifies to:
Rtotal = (R1 × R2) / (R1 + R2)