Resistor Calculator

Calculate resistor values and electrical resistance with comprehensive tools

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Resistor Calculator

The following are tools to calculate the ohm value and tolerance based on resistor color codes, the total resistance of a group of resistors in parallel or in series, and the resistance of a conductor based on size and conductivity.

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🎨 Color Code 🔗 Parallel ➕ Series 🔌 Conductor 📚 About Resistors

🎨 Resistor Color Code Calculator

Use this calculator to find out the ohm value and tolerance based on resistor color codes.

📊 Resistor Value Results

Resistor Value
52.000 MΩ
±5% (J)
1st Band (Digit) 5
2nd Band (Digit) 2
Multiplier × 1,000,000
Tolerance ±5%

🔗 Parallel Resistor Calculator

Provide all of the resistance values in parallel, separated by a comma "," and click the "Calculate" button to determine total resistance.

📊 Parallel Resistance Results

Total Parallel Resistance
1.330 Ω
Parallel circuit

Formula

1/R_total = 1/R₁ + 1/R₂ + 1/R₃ + ...
Parallel resistance is always less than the smallest individual resistor

➕ Resistors in Series Calculator

Provide all of the resistance values in series separated by a comma "," and click the "Calculate" button to determine total resistance.

📊 Series Resistance Results

Total Series Resistance
155.000 Ω
Series circuit

Formula

R_total = R₁ + R₂ + R₃ + ...
Series resistance is the sum of all individual resistances

📏 Resistance of a Conductor

Use the following to calculate the resistance of a conductor. This calculator assumes the conductor is round.

📊 Conductor Resistance Results

Conductor Resistance
4.250e-5 Ω
Round conductor
Length 100 meters
Diameter 0.05 cm
Cross-sectional Area 1.960e-6 m²
Conductivity 59,600,000 S/m

Formula

R = L / (A × C)
Where L = length, A = cross-sectional area, C = conductivity

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📚 Understanding Resistor Color Codes

Color Code System

Resistor color codes are an international standard defined in IEC 60062. Colors represent significant figures, multipliers, tolerance, and temperature coefficients.

Reading Direction

Read resistors from left to right. In 4-band resistors, there's typically a gap before the tolerance band to indicate proper orientation.

Precision Levels

5-band and 6-band resistors offer higher precision with additional significant figures and tighter tolerance specifications.

How Resistor Color Coding Works

Significant Figures: The first two (or three) bands represent significant digits of the resistance value.

Multiplier: The next band represents the power of 10 to multiply the significant figures by.

Tolerance: Indicates the percentage by which the actual resistance can vary from the nominal value.

Temperature Coefficient (6-band): Shows how resistance changes with temperature in ppm/K.

Parallel vs Series Resistance

Parallel Resistance

Total resistance is calculated using: 1/R_total = 1/R₁ + 1/R₂ + 1/R₃ + ...

Parallel resistance is always less than the smallest individual resistor.

Series Resistance

Total resistance is simply: R_total = R₁ + R₂ + R₃ + ...

Series resistance is the sum of all individual resistances.