Working with electronic components can sometimes feel like trying to crack a secret code. Inductors, specifically small axial-leaded ones, often use a color-coding system similar to resistors to denote their inductance value and tolerance. Use our professional inductor color code calculator below to quickly determine the value of your component.
How to Read Inductor Color Codes
Inductors are measured in Henries (H). However, most small electronic components are measured in microhenries (µH). The color coding on an axial inductor usually consists of four bands.
The 4-Band System Breakdown
- The First Band: Represents the first significant digit of the inductance value.
- The Second Band: Represents the second significant digit.
- The Third Band: This is the multiplier. You multiply the first two digits by the power of ten associated with this color.
- The Fourth Band: This indicates the tolerance, or the precision of the component (how much the actual value might deviate from the stated value).
Standard Color Values Table
If you prefer to calculate manually, here is the standard reference table used for inductor color codes:
| Color | Digit | Multiplier | Tolerance |
|---|---|---|---|
| Black | 0 | 1 | - |
| Brown | 1 | 10 | ±1% |
| Red | 2 | 100 | ±2% |
| Gold | - | 0.1 | ±5% |
| Silver | - | 0.01 | ±10% |
Why Do We Use Color Codes?
In the early days of manufacturing, printing tiny numbers on rounded surfaces like those of inductors and resistors was difficult and often prone to rubbing off or becoming unreadable due to heat. The color band system was developed because colors are easily identifiable from any angle and tend to be more durable than printed text.
Today, while surface-mount technology (SMT) has largely moved toward numerical codes, axial-leaded inductors remain popular in prototyping and through-hole PCB designs. Knowing how to use an inductor color code calculator is an essential skill for any hobbyist or electrical engineer.