# Inductive Reactance Calculator

URL: https://speedycalculator.com/calculators/physics/inductive-reactance/
Last updated: 2026-10-30

> The inductive reactance calculator finds the opposition an inductor presents to alternating current at a given frequency, and its susceptance.

## Inputs

- Inductance L (mH, µH, nH, H)
- Frequency f (Hz, kHz, MHz, GHz, THz, rpm)

## Results

- Inductive reactance X_L
- Susceptance B_L
- Angular frequency ω

## Formula

```
X_L = 2π·f·L = ω·L,  B_L = 1/X_L
```

## Explanation

Inductors pass DC easily but resist rapidly changing currents. Their reactance rises with frequency, which is why they are used in filters, chokes and switching power supplies.

### How to use the Inductive Reactance Calculator

- **Inductance L**
- **Frequency f**
- Every result field is editable: type into **Inductive reactance X_L** and **Frequency f** plus every other field update to match.

Results update as you type, every field has its own unit menu, and everything is calculated in your browser.

### How it works

Enter the inductance and the frequency (or type a reactance into the result to find the frequency).

### Inputs explained

FieldWhat to enterInductance LUnits: mH, µH, nH, HFrequency fUnits: Hz, kHz, MHz, GHz, THz, rpm

### What each result means

- **Inductive reactance X_L** = 2×pi×[Frequency f]×[Inductance L]
- **Susceptance B_L** = 1÷(2×pi×[Frequency f]×[Inductance L])
- **Angular frequency ω** = 2×pi×[Frequency f]

### Example values

How the main result changes when **Frequency f** changes and everything else stays at the example values above:

Frequency f (Hz)Inductive reactance X_L (Ω)50031.415975047.12391,00062.83191,25078.53981,50094.24782,000125.6637

## Worked example

Inputs — Inductance L: 10 mH; Frequency f: 1,000 Hz.

Results — **Inductive reactance X_L = 62.83185 Ω**; Susceptance B_L = 0.01592 S; Angular frequency ω = 6,283.18531 rad/s.

## Key terms

- **Susceptance**: Reciprocal of reactance.

## FAQ

**What is the reactance at DC?**
Zero – an ideal inductor is a short circuit at DC.

**Which way does the phase shift go?**
Current lags voltage by 90°.

**How is it different from resistance?**
Reactance stores and returns energy instead of dissipating it.

**What is a choke?**
An inductor used to block high-frequency currents.


## Sources

- [OpenStax – University Physics Volume 2](https://openstax.org/details/books/university-physics-volume-2)
- [HyperPhysics (Georgia State University)](http://hyperphysics.phy-astr.gsu.edu/hbase/hframe.html)