Inductor Color Code Decoder
Select inductor band colors to decode the inductance value and tolerance.
What is inductor color code decoding?
Inductors use a color band system similar to resistors to indicate their inductance value. Each color represents a digit or multiplier, and the bands are read in sequence to determine the inductance in microhenries (uH). This system is used on small through-hole inductors where printing text would be impractical.
The color code follows the same digit assignments as resistors: black = 0, brown = 1, red = 2, orange = 3, yellow = 4, green = 5, blue = 6, violet = 7, gray = 8, white = 9. The multiplier band gives the power of 10 to apply. A tolerance band indicates the precision of the stated value.
How to read the bands
A four-band inductor has two significant digit bands, one multiplier band, and one tolerance band. Read the first two bands as digits, then multiply by the multiplier to get the inductance in microhenries. For example: red-violet-orange-gold = 27 * 1000 = 27,000 uH = 27 mH, with 5% tolerance.
How to use this tool
Select the color for each band using the dropdown menus or color swatches. The tool immediately calculates and displays the inductance value with the tolerance range. You can also enter a value to find the expected color code.
Types of inductors
- Axial leaded: Small through-hole components with color bands, used for low-power signal filtering.
- Toroidal: Donut-shaped inductors wound on ferrite cores, used for EMI filtering and power supplies.
- SMD: Surface-mount inductors with printed codes, used in compact modern circuits.
- Air core: No magnetic core, used in high-frequency RF applications.
Frequently asked questions
Why do some inductors have a dot instead of bands?
Some inductors use a single dot to mark the first band position, helping you read the bands in the correct direction. The dot color represents the first digit. Other inductors, especially SMD types, use printed numeric codes similar to capacitor or resistor SMD codes.
What happens if I read the bands backwards?
Reading backwards gives a wrong value. The tolerance band (usually gold or silver) is always at the end. Start reading from the opposite end. If there is no obvious tolerance band, the first band is usually the one closest to one end of the component body.