Resistor Color Code
Decode 4-band, 5-band, and 6-band resistor color codes with this free online calculator. Get resistance value, tolerance, TCR, and min/max range instantly.
About This Calculator
The Resistor Color Code Calculator helps you decode the colored bands on through-hole resistors to determine their resistance value, tolerance, and temperature coefficient. Whether you are an electronics engineer, a hobbyist building circuits, or a student learning about electronic components, this tool converts the color bands on your resistor into precise electrical values in seconds.
The calculator supports all three common resistor band configurations: 4-band resistors with two significant digits, a multiplier, and tolerance; 5-band resistors with three significant digits for higher precision applications; and 6-band resistors that add a temperature coefficient (TCR) band for applications requiring thermal stability. The decoding follows the international IEC 60062 standard, ensuring compatibility with resistors manufactured worldwide.
The resistance value is calculated by combining the digit bands into a number and multiplying by the multiplier band. For example, a 4-band resistor with Brown (1), Black (0), and Red (×100Ω) gives 10 × 100 = 1000Ω = 1kΩ. The tolerance band then defines the acceptable range — a Gold band means ±5%, so the actual resistance could be anywhere between 950Ω and 1050Ω. For 6-band resistors, the TCR band indicates how much the resistance drifts with temperature, critical for precision analog circuits and measurement equipment.
Regional Notes
Global (IN, US, UK): Resistor color codes follow the universal IEC 60062 standard and are identical across all regions. The calculator uses SI units throughout with resistance displayed in ohms (Ω), kilo-ohms (kΩ), mega-ohms (MΩ), or giga-ohms (GΩ) depending on the value. Tolerance is expressed as a percentage, and TCR in ppm/°C — both are internationally standardized measurements used by electronics manufacturers everywhere.
Frequently Asked Questions
How do I read a resistor color code?
To read a resistor color code, identify the first band (closest to the end), then read the digits from left to right. For a 4-band resistor, the first two bands are digits, the third is the multiplier, and the fourth is the tolerance. Use the color-to-digit chart: Black=0, Brown=1, Red=2, Orange=3, Yellow=4, Green=5, Blue=6, Violet=7, Gray=8, White=9.
What is the difference between 4-band, 5-band, and 6-band resistors?
4-band resistors have two significant digits, a multiplier, and a tolerance band. 5-band resistors have three significant digits for higher precision, a multiplier, and a tolerance band. 6-band resistors add a sixth band for the temperature coefficient (TCR), which indicates how much the resistance changes with temperature.
What is the 10k resistor color code?
For a 4-band 10kΩ resistor with 5% tolerance, the color code is Brown-Black-Orange-Gold. The first band Brown=1, second Black=0, third Orange=×1kΩ, giving 10 × 1000 = 10kΩ, and Gold indicates ±5% tolerance. For a 5-band 10kΩ resistor with 1% tolerance, the code is Brown-Black-Black-Red-Brown.
How do I know which end of a resistor to read from?
Look for the larger gap between bands — this gap appears before the tolerance band. The bands grouped closer together are the digits and multiplier, and you read from the side with these grouped bands. If the resistor has a gold or silver band, that is always the tolerance band at the end. The first band is typically closest to the edge of the resistor.
What do the tolerance colors mean on a resistor?
Tolerance indicates how much the actual resistance can vary from the stated value. Common tolerances include: Gold=±5%, Silver=±10%, Brown=±1%, Red=±2%, Green=±0.5%, Blue=±0.25%, Violet=±0.1%, and Gray=±0.05%. Lower tolerance percentages indicate more precise resistors that are more expensive.
What is TCR (Temperature Coefficient of Resistance)?
TCR (Temperature Coefficient of Resistance) measures how much a resistor's value changes with temperature, expressed in ppm/°C. For example, a resistor with 100 ppm/°C TCR changes by 0.01% per degree Celsius. Common TCR values are: Brown=100, Red=50, Yellow=25, Orange=15, Blue=10, and Violet=5 ppm/°C. Lower TCR values mean better temperature stability.
Are resistor color codes standardized worldwide?
Yes, resistor color codes follow the international IEC 60062 standard (also BS 1852). This standard defines the color-to-digit mapping, multiplier values, and tolerance codes. The standard is universally adopted by all major resistor manufacturers worldwide, making resistor color codes consistent across countries and brands.
What color is a 220 Ohm resistor?
A 4-band 220Ω resistor with ±5% tolerance has the color code Red-Red-Brown-Gold. The first Red=2, second Red=2, third Brown=×10Ω, giving 22 × 10 = 220Ω, and Gold indicates ±5% tolerance. For a ±10% tolerance version, the last band would be Silver instead of Gold.