Resistor Color Code Calculator,
decode any band configuration.

Field guide

How to read resistor color codes.

Color coding is the standard way to mark resistance values on small axial resistors where printing numbers directly is impractical. The system is defined by IEC 60062 and has been in use since the 1920s. Each colored band encodes either a significant digit, a power-of-ten multiplier, a tolerance percentage, or — on precision components — a temperature coefficient.

The four-band resistor (most common)

Most general-purpose resistors use four bands. Reading left to right (starting from the end nearest the lead):

• Band 1: first significant digit (0–9)
• Band 2: second significant digit (0–9)
• Band 3: multiplier (×1 through ×1 GΩ, or ×0.1 / ×0.01 for Gold / Silver)
• Band 4: tolerance (Gold = ±5%, Silver = ±10%, no band = ±20%)

Worked example: Brown, Black, Red, Gold:

The five-band resistor (precision)

Five-band resistors encode three significant digits instead of two, allowing more precise value specification. They are used where tighter tolerances (±1%, ±0.5%, ±0.25%, ±0.1%) are required:

• Bands 1–3: three significant digits
• Band 4: multiplier
• Band 5: tolerance

Worked example: Brown, Black, Black, Red, Brown:

The six-band resistor (temperature-stable)

Six-band resistors add a sixth band indicating the temperature coefficient: how much resistance changes per degree Celsius. This matters in applications like precision instrumentation, oscillators, and filters where thermal drift must be controlled:

• Bands 1–3: three significant digits
• Band 4: multiplier
• Band 5: tolerance
• Band 6: temperature coefficient (ppm/°C)

Which end do I start from?

The Gold or Silver tolerance band is almost always on the right side of the resistor, so start reading from the left. On 5- and 6-band resistors there is usually a wider gap between the multiplier band and the tolerance band, which also helps you orient the component correctly.

If you're ever unsure, the calculator above lets you enter bands from either direction. If the result looks implausible (e.g., a multiplier of Gold where a digit is expected), try reversing the order.

Color code reference chart

The twelve colors used in resistor coding, with their digit, multiplier, tolerance, and temperature coefficient values:

Tolerance and what it means in practice

The tolerance band tells you how close the actual resistance must be to the marked value. For a 10 kΩ resistor:

• ±5% (Gold): actual value between 9,500 Ω and 10,500 Ω
• ±1% (Brown): actual value between 9,900 Ω and 10,100 Ω
• ±0.1% (Violet): actual value between 9,990 Ω and 10,010 Ω

For audio circuits, voltage dividers, and filters, tighter tolerances improve performance predictability. For LED current limiting, pull-up/pull-down resistors, and most digital logic applications, ±5% is entirely adequate.

Temperature coefficient explained

The temperature coefficient (TC) on a 6-band resistor tells you how much resistance shifts per degree Celsius, expressed in parts per million (ppm). A 10 kΩ resistor with a 100 ppm/°C TC will change by:

This shift of 30 Ω represents a 0.3% change — significant for precision circuits, irrelevant for many general-purpose designs. Metal film resistors typically carry 50–100 ppm/°C; precision wirewound types can reach 1–5 ppm/°C.

Disclaimer

This calculator follows IEC 60062 and is intended for educational and prototyping use. Always verify critical values with a calibrated multimeter before using resistors in safety-critical or high-precision designs.