Inductor Calculator
Calculate inductor reactance from inductance and frequency, or estimate inductance from coil dimensions.
Essential for RF and circuit design.
Inductor Results
Inductive reactance is the opposition an inductor presents to alternating current:
X_L = 2π × f × L
Where:
- X_L = inductive reactance (ohms)
- f = frequency (Hz)
- L = inductance (henrys)
Single-layer coil inductance (Wheeler’s formula):
L (µH) = (d² × N²) / (18d + 40l)
Where:
- d = coil diameter (inches)
- N = number of turns
- l = coil length (inches)
Common inductance values:
| Application | Typical Range |
|---|---|
| RF circuits | 1 nH – 10 µH |
| Audio filters | 10 µH – 100 mH |
| Power supply chokes | 1 mH – 10 H |
| EMI filters | 100 µH – 10 mH |
Key relationships:
- Higher frequency → higher reactance
- More turns → more inductance (squared relationship)
- Larger diameter → more inductance
- Core material greatly affects inductance (ferrite adds 100–10,000×)