How to use the resistor color code calculator
To use the resistor color code calculator click on the resistor color bands on the left. Then you can select the color for each band. The calculator will automatically show you the resistance value, tolerance, and temperature coefficient band. You can also use the up and down arrows to change the band colors sequentially. Use the selector to switch between 4-band, 5-band, and 6-band resistor formats.
What is the Resistor Color Code
Axial resistors (also called thru-hole resistors) use a color-band system (EIA) to indicate their nominal resistance, tolerance, and, in some cases, temperature coefficient. Each color corresponds to a specific number or multiplier. For example, black represents 0, brown 1, red 2, orange 3, yellow 4, green 5, blue 6, violet 7, gray 8, and white 9. The colors for multipliers and tolerances are also standardized. This coding system allows manufacturers to label very small components without printing text. Band meaning summary:
- First and second band: significant digits
- Third band: multiplier
- Fourth band: tolerance
- Fifth band (if present): extra significant digit (it is in 3rd position after first and second bands)
- Sixth band (if present): TCR (temperature coefficient)
Resistor color codes are standardized according to international electronics norms and are used in almost all through-hole axial resistors.
Resistor Color Code Chart
The resistor color code chart summarizes the digits, multipliers, and tolerances assigned to each color. It is the universal reference used to decode through-hole resistors.
You can download the resistor color chart as a PNG:
Download chart.
What is Resistor Tolerance?
Tolerance indicates how much the actual resistance can vary from its nominal value. For example, a 1 kΩ resistor with ±5% tolerance may range between 950 Ω and 1050 Ω. Low-tolerance resistors (1%, 0.1%) are used in precision circuits, sensors, filters, and applications where stable and predictable resistance is required.
What is TCR (Temperature Coefficient of Resistance)?
The Temperature Coefficient of Resistance (TCR) describes how much the value of a resistor changes with temperature. It is expressed in parts per million per degree Celsius (ppm/°C). A lower TCR means better thermal stability. For example, imagine a 10 kΩ resistor with a TCR of 100 ppm/°C. If the temperature rises from 25 °C to 50 °C (a 25 °C increase), the resistance change is:
100 ppm x 25 °C = 2500 ppm = 0.25%
This means the resistor will increase by 0.25% of its nominal value:
10 kΩ x 0.0025 = 25 Ω,
so at 50 °C the resistor would be approximately 10025 Ω. Resistors with low TCR values are essential in precision analog circuits, oscillators, feedback networks, and any application where temperature variations can affect performance.
Example
Imagine you have a 5-band resistor with the following colors: Yellow – Violet – Black – Red – Gold
This corresponds to:
- 4 (yellow)
- 7 (violet)
- 0 (Black)
- ×100 (red multiplier)
- ±5% (gold tolerance)
The value is 47 kΩ ±5%.
If we add a sixth band Brown, the TCR would be 100 ppm/°C.
Frequently Asked Questions
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How do you read a 4-band resistor?
First two bands are digits, third is the multiplier, fourth is tolerance.
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How do you read a 5-band resistor?
Three digits, one multiplier, and a tolerance band.
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How do you read a 6-band resistor?
Same as 5-band, with an extra band indicating TCR (temperature coefficient).
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Why do resistors use color codes?
Because axial resistors are too small to print values on, so standardized color bands are used instead.
