Inductor Color Code Calculator
Read the two digits, multiplier and tolerance of a four-band inductor to find its inductance and tolerance range.
Inputs and reverse calculation
Calculated results
| Inductance | 1 µH |
|---|---|
| Tolerance and range | ±10%; 900 nH–1.1 µH |
| Band sequence | Brown → Black → Gold → Silver |
How to interpret the result
This tool reads the four-band digit–digit–multiplier–tolerance scheme. The multiplier applies to microhenries; results are stored in henries and displayed with a suitable prefix. Confirm that the component is an inductor and place the tolerance band last. Check the part number when an axial component resembles a resistor.
Formulas and units
L[H]=(10A+B)×M×10⁻⁶. Gold has M=0.1 and silver M=0.01. The tolerance interval is L×(1±t/100). This scheme uses black 20%, brown 1%, red 2%, orange 3%, yellow 4%, gold 5% and silver 10% tolerances.
Worked example
Yellow–violet–gold–gold gives 47×0.1=4.7 µH, ±5%, or 4.465–4.935 µH. The default brown–black–gold–silver combination gives 1 µH, ±10%.
Scope and limitations
This decoder covers this four-band scheme only and does not infer bands from a value. It does not cover military identification bands, five-band decimal-point schemes or manufacturer-specific color dots referenced to nH. Bands do not specify saturation current, DC resistance or self-resonant frequency.
Common questions
Why can I not read it as a resistor?
The digit method is similar, but the base unit here is µH. Yellow–violet–gold means 4.7 µH, rather than 4.7 Ω.
Why are some colors unavailable as multipliers?
The multiplier table used here includes black through yellow, plus gold and silver. If a component uses another multiplier or band count, consult its manufacturer’s data sheet.
Can I replace a part using inductance alone?
Also match rated and saturation current, DC resistance, frequency behavior and size. Bands identify only nominal inductance and tolerance.
Related tools
Formula and data sources
- Tony R. Kuphaldt: Components and inductor markings
- Bourns: alternative color-band and military markings
Rebuilt from the extracted Electrodoc Pro 5.2 specification. Added, inferred and corrected behavior is identified in the limitations. Updated 2026-11-13.