Resistor Calculator

- May 10, 2025
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Calculate resistor values using colour bands or determine the colour bands for a given resistance value. This calculator supports 4-band, 5-band, and 6-band resistors with temperature coefficients.

Select Operation

Resistor Type

Options

About Resistor Colour Codes

Resistors use colour bands to indicate their resistance value, tolerance, and sometimes temperature coefficient. The standard colour code system helps engineers and technicians identify resistor values without using measuring equipment.

Colour Code Chart
Colour Digit Value Multiplier Tolerance Temp. Coeff. (ppm/°C)
Black 0 ×1 - -
Brown 1 ×10 ±1% 100
Red 2 ×100 ±2% 50
Orange 3 ×1,000 - 15
Yellow 4 ×10,000 - 25
Green 5 ×100,000 ±0.5% -
Blue 6 ×1,000,000 ±0.25% 20
Violet 7 ×10,000,000 ±0.1% 10
Grey 8 ×100,000,000 ±0.05% 5
White 9 ×1,000,000,000 - 1
Gold - ×0.1 ±5% -
Silver - ×0.01 ±10% -
Types of Resistors by Band Count
  • 4-Band Resistors: Most common type with two significant digits, a multiplier, and a tolerance band
  • 5-Band Resistors: Higher precision resistors with three significant digits, a multiplier, and a tolerance band
  • 6-Band Resistors: Highest precision with three significant digits, a multiplier, a tolerance band, and a temperature coefficient band
Reading Resistor Colour Bands

To read a resistor's value:

  1. Orient the resistor with the tolerance band (gold/silver/etc.) to the right
  2. Read the colour bands from left to right
  3. For 4-band resistors: First two bands are digits, third is multiplier, fourth is tolerance
  4. For 5-band resistors: First three bands are digits, fourth is multiplier, fifth is tolerance
  5. For 6-band resistors: Like 5-band, with the sixth band indicating temperature coefficient
Temperature Coefficient

The temperature coefficient (in ppm/°C) indicates how much the resistance changes with temperature:

  • A lower value means more stability across temperature changes
  • Only found on high-precision 6-band resistors
  • Calculated as: ΔR/R = α × ΔT where α is the temperature coefficient

Introduction to the Resistor Calculator

The Resistor Calculator is a handy tool designed for anyone who works with electronics. It helps you calculate resistor values using colour bands or determine the colour bands for a given resistance value. This tool is suitable for various types of resistors, including 4-band, 5-band, and 6-band configurations, making it versatile for different applications.

Understanding Resistor Colour Codes

Resistors use colour bands to indicate their resistance values, tolerances, and sometimes temperature coefficients. Each colour corresponds to a specific number or multiplier, letting you quickly figure out a resistor's specifications. For example:

  • Black stands for 0
  • Brown represents 1
  • Red is for 2
  • Gold and silver indicate tolerance levels

How to Use the Calculator

The Resistor Calculator allows you to choose your calculation method easily. You can select whether you want to convert colour bands into resistance values or convert a specific resistance value into colour bands. This feature ensures that you can always get the information you need, regardless of your starting point.

Input Options for Different Resistor Types

You can select from different types of resistors based on the number of bands. The calculator supports:

  • 4-band resistors for basic applications
  • 5-band resistors for higher precision
  • 6-band resistors for the most accurate readings, including temperature coefficients

Calculation Features and Results

Once you input your values, the Resistor Calculator provides a detailed breakdown of the results. You’ll receive the calculated resistance value, tolerance, and temperature coefficient if applicable. This information can be crucial for ensuring your electronics projects function correctly.

Visualisation of Resistor Values

One exciting feature of the Resistor Calculator is its visualisation option. After entering the colour bands, you can see a graphic representation of what the resistor looks like. This visual aid helps in understanding how the colours correspond to the resistor's value and gives a clearer picture of what you're working with.

Showing Calculation Steps

The calculator can also display the calculation steps taken to arrive at the final results. This feature is especially beneficial for students and beginners who want to learn how to interpret resistor values. By following the steps, you can gain insights into the calculations behind the scenes.

Conclusion on the Resistor Calculator's Benefits

The Resistor Calculator is an invaluable tool for electronics enthusiasts, students, and professionals alike. With its user-friendly interface, detailed results, and educational features, it simplifies the often complicated task of working with resistors. Whether you need to convert values or simply learn more about resistor colour codes, this calculator has you covered.