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Resistor Calculator

Calculate resistor color codes or find the equivalent resistance for series and parallel circuits.

-- Ω
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Limit Range--
E-Series Status--
Exact Multiplier Math
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How to use Resistor Calculator

  1. Select the calculation tab: Color Code or Series/Parallel.
  2. For Color Code: Choose 4 or 5 bands, then select the color for each band to see the value update.
  3. For Series/Parallel: Input comma-separated resistor values (e.g. 100, 220, 470) and choose the connection type.

What is Resistor Calculator?

A resistor is a passive electrical component that creates resistance in the flow of electric current. This dual-purpose utility calculates:

  • Resistor Color Code: Determines the resistance value and tolerance based on selected color bands for 4-band and 5-band resistors.
  • Series and Parallel Resistance: Calculates the equivalent resistance (Req) of multiple resistors connected together.
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FAQ

What is the E24 standard?
The E24 series is a set of standard preferred resistor values with a 5% tolerance, widely used in electronics design.
How are parallel resistors calculated?
Parallel equivalent resistance is calculated using the formula: 1/Req = 1/R1 + 1/R2 + ... + 1/Rn. The total parallel resistance is always smaller than the smallest individual resistor.

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Author

OH
Omar Hassan"The Number Cruncher"

Engineer & Unit Conversion Specialist

Omar is a mechanical engineer by training and a unit-conversion enthusiast by passion. He has built calibration systems for aerospace and automotive manufacturers and knows firsthand how a single decimal error can cost millions in rework. His mission is to make every conversion instant, accurate, and accessible to everyone, whether they are a student, tradesperson, or practicing engineer, with no advanced degree required.

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