Resistor color bands

The colored bands on resistors encode value, tolerance, and temperature coefficient according to the international IEC 60062 standard.

About this subject

Resistors are passive components that limit electric current flow in electronic circuits. Through-hole resistors use colored bands printed on their body to indicate resistance value, tolerance, and temperature coefficient. This coding system was standardized by the Radio Manufacturers Association (RMA) in the 1920s and later adopted by IEC 60062, ensuring readability even on tiny components.

The most common coding uses 4 bands: the first two are significant digits, the third is the multiplier (power of 10), and the fourth is tolerance. For example, a resistor with brown, black, red, and gold bands equals 10 × 100 = 1000 ohms (1 kΩ) with 5% tolerance. There are 5-band variants (higher precision) and 6-band variants (including temperature coefficient). Colors follow the rainbow sequence from black (0) to white (9), with gold and silver for fractional multipliers and special tolerances.

Correct reading is essential for circuit assembly and repair. Surface-mount resistors use numeric codes, but color bands still dominate larger components and educational kits. Misreading can cause malfunction or component burnout. Therefore, color code charts and online calculators are useful tools for students and technicians.

Trivia: the resistor body color (beige, blue, gray) does not affect the code and usually indicates material type or manufacturer. The temperature coefficient (in ppm/°C) is important in high-precision applications like instrumentation and professional audio.

Frequently Asked Questions

What do the colored bands on a resistor mean?

The colored bands encode the resistance value (in ohms), tolerance (precision), and for 6-band resistors, the temperature coefficient. Each color represents a digit from 0 to 9, following the sequence black, brown, red, orange, yellow, green, blue, violet, gray, white.

How do I read a 4-band resistor?

The first two bands are significant digits, the third is the multiplier (10 raised to the power of the color), and the fourth is tolerance. For example, brown (1), black (0), red (×100), gold (±5%) gives 10 × 100 = 1000 Ω with 5% tolerance.

Why do some resistors have 5 or 6 bands?

5-band resistors provide higher precision (tolerances of 1% or less) by adding a third significant digit. 6-band resistors include an additional band for the temperature coefficient, important in critical applications where resistance changes with temperature.