In electronics, resistors are one of the most common components. They limit current flow, divide voltages, and protect sensitive parts in circuits. However, unlike other components, resistors do not always display their resistance value as a number—most use colour bands to indicate their specifications.
Resistor Colour Coding Calculator
What is Resistor Colour Coding?
Resistor colour coding is a method of indicating a resistor’s value using coloured bands painted around the component’s body. Each colour corresponds to a specific number, multiplier, or tolerance.
The most common formats are:
4-band resistors (two value bands, one multiplier band, one tolerance band)
5-band resistors (three value bands, one multiplier, one tolerance)
6-band resistors (five value bands, multiplier, tolerance, and temperature coefficient)
By interpreting the colours, you can determine the resistor’s resistance in ohms (Ω) and its precision.
Why Use a Resistor Colour Coding Calculator?
While it’s possible to learn and memorize the resistor colour code chart, doing so takes time, and manual calculations can be prone to errors. A Resistor Colour Coding Calculator provides:
Instant results – No need to cross-check with charts
Error-free decoding – Reduces mistakes from manual interpretation
Support for multiple resistor types – Works for 4, 5, and 6-band resistors
Convenience – Perfect for quick reference during projects
How to Use the Resistor Colour Coding Calculator
Using this calculator is simple and straightforward:
Select the number of bands
Choose whether your resistor has 4, 5, or 6 bands.
Identify and select each colour
Starting from one end of the resistor, choose the colours in sequence from the drop-down or colour picker.
View the results
The calculator will display the resistance value in ohms, tolerance percentage, and temperature coefficient (if applicable).
Repeat for other resistors
You can decode multiple resistors quickly by repeating the process.
Resistor Colour Code Table
Here is the standard resistor colour code reference:
Colour Digit Multiplier Tolerance
Black 0 1 Ω —
Brown 1 10 Ω ±1%
Red 2 100 Ω ±2%
Orange 3 1 kΩ —
Yellow 4 10 kΩ —
Green 5 100 kΩ ±0.5%
Blue 6 1 MΩ ±0.25%
Violet 7 10 MΩ ±0.1%
Grey 8 100 MΩ ±0.05%
White 9 1 GΩ —
Gold — 0.1 Ω ±5%
Silver — 0.01 Ω ±10%
None — — ±20%
Formula for Resistor Colour Calculation
For a 4-band resistor:
Resistance (Ω) = [(Band1 × 10) + Band2] × Multiplier
For a 5-band resistor:
Resistance (Ω) = [(Band1 × 100) + (Band2 × 10) + Band3] × Multiplier
Tolerance is determined by the last band.
Example Calculations
Example 1 – 4-Band Resistor
Colours: Red (2), Violet (7), Yellow (×10,000), Gold (±5%)
Resistance = [(2 × 10) + 7] × 10,000
Resistance = (20 + 7) × 10,000 = 270,000 Ω (270 kΩ) ±5%
Example 2 – 5-Band Resistor
Colours: Brown (1), Black (0), Red (2), Orange (×1,000), Brown (±1%)
Resistance = [(1 × 100) + (0 × 10) + 2] × 1,000
Resistance = (100 + 0 + 2) × 1,000 = 102,000 Ω (102 kΩ) ±1%
Benefits of Using the Calculator
Saves time in decoding
Reduces human error
Supports different resistor formats
Helps beginners and professionals alike
Useful in educational settings for learning the code
Tips for Accurate Results
Always start reading from the end closest to the tolerance band (gold/silver).
Ensure lighting is adequate—colour perception can change under dim light.
Double-check resistor orientation before entering colours.
If in doubt, use a multimeter to confirm the value.
Store resistors in labeled compartments to avoid confusion.
20 Frequently Asked Questions (FAQs)
- What is a resistor colour code?
It’s a method of marking resistors with coloured bands to indicate resistance and tolerance. - How many bands can a resistor have?
Commonly 4, 5, or 6 bands. - What do the first two bands represent?
They indicate the first digits of the resistance value. - What does the multiplier band do?
It tells you by what factor to multiply the base number. - What is the tolerance band?
It shows how accurate the resistor value is compared to its stated resistance. - Why use a colour code instead of numbers?
It saves space and is easy to print on small components. - Can I identify resistor values without a calculator?
Yes, by memorizing the colour chart. - What does a gold multiplier mean?
Multiply the base value by 0.1. - What is the silver multiplier?
Multiply the base value by 0.01. - Are resistor colours universal?
Yes, they follow international standards like IEC 60062. - What is the 6th band in a resistor?
Usually indicates the temperature coefficient. - Do SMD resistors use colour codes?
No, they use numerical markings. - Can a calculator handle 6-band resistors?
Yes, many calculators include temperature coefficient decoding. - Why does tolerance matter?
It determines how close the actual resistance is to the stated value. - What if colours are faded?
Use a multimeter to confirm the value. - Can resistor values change over time?
Yes, due to heat, moisture, or aging. - What is the most common tolerance in resistors?
±5% for general-purpose resistors. - What do precision resistors use?
Tighter tolerances like ±0.1% or ±0.25%. - Can the calculator work offline?
If it’s a software or app version, yes. - Is this calculator good for beginners?
Absolutely, it simplifies learning resistor colour codes.