Inductive Reactance
XL = 2πfL
Quick answer
This calculator solves XL = 2πfL for Reactance. With Frequency 100 kHz, Inductance 10 mH, the result is 6.283 kΩ. It solves in 3 directions, so you can enter the values you have and get the one you need.
Calculator
Formula
Description
Inductive reactance is the opposition an inductor presents to alternating current, and it increases linearly with both frequency and inductance. This is the opposite behavior of capacitive reactance, which decreases with frequency. The physical basis is Faraday's law: a changing current through the inductor creates a changing magnetic field, which induces a back-EMF that opposes the change. At DC (0 Hz) an ideal inductor is a short circuit with zero reactance, while at very high frequencies it approaches an open circuit.
Variables
- XL — Inductive reactance in ohms (Ω)
- f — Frequency in hertz (Hz)
- L — Inductance in henries (H)
Practical Notes
Inductive reactance causes voltage to lead current by 90 degrees, the exact opposite of capacitive reactance. This complementary behavior is what enables LC resonant circuits and is exploited in filter design, impedance matching, and power factor correction.
Symbols and units
| Symbol | Meaning | Default unit | Accepted units |
|---|---|---|---|
| XL | Reactance | Ω | mΩ, Ω, kΩ, MΩ |
| f | Frequency | kHz | Hz, kHz, MHz, GHz |
| L | Inductance | mH | nH, µH, mH, H |
Step by step
- 1. What you know: Frequency 100 kHz, Inductance 10 mH
- 2. The relation: XL = 2πfL
- 3. Substitute: f = 100 kHz, L = 10 mH
- 4. Result: Reactance = 6.283 kΩ
Nearest standard component values
| Series | Nearest value | Error |
|---|---|---|
| E12 | 6.8 kΩ | 8.2% |
| E24 | 6.2 kΩ | 1.3% |
Worked examples
Minimum range
Given: Frequency 100 Hz, Inductance 100 µH
Result: Reactance = 62.83 mΩ
Low range
Given: Frequency 1 kHz, Inductance 1 mH
Result: Reactance = 6.283 Ω
Typical
Given: Frequency 100 kHz, Inductance 10 mH
Result: Reactance = 6.283 kΩ
High range
Given: Frequency 0.5 MHz, Inductance 100 mH
Result: Reactance = 0.3142 MΩ
Maximum range
Given: Frequency 5 MHz, Inductance 1 H
Result: Reactance = 31.42 MΩ
Solving for each variable
Solve for Reactance
Frequency 100 Hz, Inductance 100 µH → 62.83 mΩ
Solve for Frequency
Reactance 1 Ω, Inductance 100 µH → 1.592 kHz
Solve for Inductance
Reactance 1 Ω, Frequency 100 Hz → 1.592 mH
How Reactance changes with Frequency
| Frequency (input) | Reactance (result) |
|---|---|
| 10 kHz | 0.6283 kΩ |
| 25 kHz | 1.571 kΩ |
| 50 kHz | 3.142 kΩ |
| 75 kHz | 4.712 kΩ |
| 100 kHz | 6.283 kΩ |
| 150 kHz | 9.425 kΩ |
| 0.2 MHz | 12.57 kΩ |
| 0.4 MHz | 25.13 kΩ |
| 0.7 MHz | 43.98 kΩ |
| 1 MHz | 62.83 kΩ |
The same result in other units
| Unit | Value |
|---|---|
| mΩ | 6283000 |
| Ω | 6283 |
| kΩ | 6.283 |
| MΩ | 0.006283 |
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<p><a href="https://vbatpower.com/formulas/inductive-reactance/">Inductive Reactance</a> Calculator by vbatpower.com</p>Frequently asked questions
How do you calculate Inductive Reactance?
Use XL = 2πfL. With Frequency 100 kHz, Inductance 10 mH, Reactance works out to 6.283 kΩ.
What is the formula for Inductive Reactance?
The formula is XL = 2πfL. Inductive reactance is the opposition an inductor presents to alternating current, and it increases linearly with both frequency and inductance.
How do you find Frequency when you know the other values?
Rearrange for Frequency: with Reactance 1 Ω, Inductance 100 µH, Frequency is 1.592 kHz.
How do you find Inductance when you know the other values?
Rearrange for Inductance: with Reactance 1 Ω, Frequency 100 Hz, Inductance is 1.592 mH.
What units does Inductive Reactance use?
Reactance is shown in mΩ, Ω, kΩ, MΩ. Values are held in SI base units internally, so you can mix prefixes without converting by hand.
Related Concepts
All Inductors formulas →Need more features?
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