Welcome to ElectroDuino’s Resistor Colour Code Calculator. This is a free, easy-to-use tool to quickly find the resistance value of 3-band, 4-band, 5-band, and 6-band resistors using their color bands.

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How to Use the Resistor Color Code Calculator

Reading resistor’s resistance values from the color bands can be confusing and time taking, especially for beginners. Our Resistor Colour Code Calculator makes this process faster, accurate, and effortless. 

Below is a complete step by step guide to help you decode 3-band, 4-band, 5-band, and 6-band resistors using our online tool. Follow the step-by-step instructions below:

✅ Step 1: Examine the Resistor and Count the Bands

First, take a physical resistor in your hand and examine it carefully. Now count the number of coloured bands printed on the body of the resistor. You’ll typically find:

• 3 Colour Bands: Older or low-precision resistors (less common)
• 4 Colour Bands: Most commonly used standard fixed resistors (most common)
• 5 Colour Bands: Precision resistors with more accurate values (1% or better tolerance)
• 6 Colour Bands: High-precision resistors with temperature coefficient

📌 Tip: Hold the resistor in your hand so that the tolerance band (usually gold or silver) is on the right side. This ensures you’re reading the colour bands in the correct left-to-right order.

 

✅ Step 2: Select the Number of Bands in the Calculator

Once you’ve identified how many bands are present on your physical resistor, Now come to the Calculator and select the appropriate band type from the dropdown menu:

👉 3-Band | 4-Band | 5-Band | 6-Band

This step ensures the calculator displays the correct number of band selectors and applies the right logic for calculating resistance value 

 

✅ Step 3: Select the Colour for Each Band

For each resistor band (Band 1, Band 2, Multiplier, Tolerance, and Temp Coefficient) has a dedicated color selection column showing in the color chart present below the resistor graphic.

Simply click on the colour box that matches the band colour on your physical resistor. The Color code chart follows the standard resistor colour code — including Black, Brown, Red, Orange, Yellow, Green, Blue, Violet, Grey, White, Gold, and Silver.

Once you click a colour a green border will highlight your selected colour in the chart. The corresponding band on the resistor graphic instantly updates automatically to reflect your selection.

📌 Tip: You can change any band colour anytime just by clicking another colour box. If you select the wrong colour, simply click the correct one — the calculator updates instantly.

 

✅ Step 4: Read the Calculated Resistance Value

Once you’ve selected all the colour bands using the color chart, the Resistor Colour Code calculator instantly displays the resistance value along with additional important details. This step gives you the final resistance value, tolerance, and temperature coefficient (For 6-band resistors only) of your physical resistor.

🔍 What You’ll See in the Output:

1. Resistance Value

 You can see the calculated resistance value in the output section, which measured in:

• Ohms (Ω)
• Kilo-ohms (kΩ)
• Mega-ohms (MΩ)

The value is formatted with proper units and SI notation, making it easy to read at a glance.

 

2. Tolerance Value (%) – Accuracy of the Resistor

Beside the Resistance value, you can see the tolerance value. This defines how much the actual resistance value can vary from the labeled value of the resistor.

Expressed as a percentage (±%), based on the colour of the tolerance band.

✅ Common Tolerance Values:

• Gold = ±5%
• Silver = ±10%
• Brown = ±1%
• Red = ±2%

 

3. Temperature Coefficient (For 6-band resistors only)

For 6-band resistors, an additional 6th band is used to show the temperature coefficient, usually measured in ppm/°C (Parts Per Million per Degree Celsius). This tells how the resistance changes as temperature increases.

✅ Typical values:

• Brown = 100 ppm/°C
• Red = 50 ppm/°C
• Orange = 15 ppm/°C