Inductance Converter

Convert inductance values across 9 units instantly — the practical SI range from picohenries to kilohenries (pH, nH, µH, mH, H, kH), plus the legacy CGS units abhenry and stathenry, and the weber-per-ampere (Wb/A) flux-linkage equivalent. Enter a value from a coil measurement, component datasheet, or motor nameplate, and see it converted across every supported unit at once. Results include the exact formula used, a quick reference table, and two built-in quick calculators — Inductive Reactance (X_L = 2πfL) and Energy Stored (E = ½LI²) — plus an optional custom-unit slot for proprietary or non-standard specs. Built for electricians, RF and electronics engineers, drone and robotics hobbyists, and students working with inductors, coils, chokes, and transformers.

Enter an inductance value and select its unit. Formula: Henry = Value × Unit Factor, then each target unit = Henry ÷ Target Factor.

Inductance Value

Inductance Unit —
SI & Legacy CGS Units

SI Henry Units

Picohenry

—

Nanohenry

—

Microhenry

—

µH

Millihenry

—

Henry

—

Kilohenry

—

Legacy CGS & Derived Units

Abhenry

—

abH

Stathenry

—

statH

Weber / Ampere

—

Wb/A

Formula: —

Quick Calculators

Inductive Reactance

Enter a frequency to find X_L for the inductance value above.

—

X_L = 2πfL

Energy Stored

Enter a current to find the energy stored in the magnetic field.

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E = ½LI²

Custom Unit

For a proprietary or non-standard spec — e.g. a drone/robotics component unit.

—

Value = Henry ÷ Your Factor

User-supplied conversion factor — not a verified engineering unit. Independently confirm this factor before relying on the result for any design work.

Conversions are mathematically exact for SI-prefixed units. Abhenry and Wb/A conversions are exact by definition; the stathenry conversion factor is a published CGS-ESU constant.

How to Use the Inductance Converter

Enter Your Inductance Value

Type the inductance value from a coil measurement, component datasheet, or motor nameplate into the input field.

Select the Source Unit

Choose the unit your value is currently in — SI Henry Units (Picohenry through Kilohenry) or Legacy CGS & Derived Units (Abhenry, Stathenry, Wb/A) are both supported.

Click Calculate

The converter instantly computes the equivalent value in all 9 supported inductance units at once, grouped for quick scanning — no need to convert one pair at a time.

Run the Quick Calculators and Print

Optionally enter a frequency for inductive reactance or a current for energy stored. Use Print to capture results as they appear on screen for documentation.

Guide to Inductance Units Comprehensive Guide

A deeper look at where each inductance unit on this page comes from, plus how the two quick calculators and the custom-unit slot work.

SI-Prefixed Units (Picohenry through Kilohenry)

Picohenry, Nanohenry, Microhenry, Millihenry, Henry, and Kilohenry are all the same underlying unit — the henry — scaled by a power of ten, per the International System of Units (SI) convention. Because every SI conversion is an exact power of ten, there is no rounding error going between any two of these units.

Legacy CGS Units — Abhenry & Stathenry

The abhenry comes from the older CGS-EMU (electromagnetic) system and equals exactly 1×10⁻⁹ henry — the same magnitude as a nanohenry. The stathenry comes from the CGS-ESU (electrostatic) system and equals approximately 8.9876×10¹¹ henries, an enormous value derived using the speed of light as the conversion constant between the two systems. Both units appear mainly in older texts and theoretical physics rather than everyday electronics.

Weber per Ampere (Wb/A)

The henry is formally defined as one weber of magnetic flux linkage per ampere of current (1 H = 1 Wb/A), so this is not a separate scale — it's the same unit expressed through its flux-linkage definition rather than its name.

Inductive Reactance (X_L = 2πfL)

Inductive reactance is the opposition an inductor presents to alternating current, measured in ohms. It rises with both frequency and inductance — double the frequency and reactance doubles, double the inductance and reactance doubles. This quick calculator takes the henry value from the converter above and the frequency you enter to compute X_L directly.

Energy Stored (E = ½LI²)

An inductor stores energy in its magnetic field while current flows through it. That stored energy, in joules, depends on the inductance and the square of the current — doubling the current quadruples the stored energy. This quick calculator takes the henry value from the converter above and the current you enter to compute the stored energy directly.

Custom Unit

Some drone, robotics, or proprietary component specs use a non-standard inductance unit. Toggle on Custom Unit, give it a label and its conversion factor in henries, and the calculator converts your entered value into that unit live. Because the factor is supplied by you rather than a published standard, always independently verify it before relying on the result.

This guide is provided for educational and reference purposes. Always confirm measured inductance values against a properly calibrated instrument before relying on them for any electrical or mechanical work.

Worked Examples

Three real-world conversion scenarios, worked step by step. Click "Load This Example" to run it in the calculator above.

1. Antenna Coil — Microhenry to Nanohenry

A 150 µH antenna coil needs to be specified in nanohenries for a PCB layout tool. Convert 150 µH to nH.

150 µH × 1,000 = 150,000 nH

2. Power Transformer — Henry to Millihenry

A power-supply transformer has 2.5 H of primary inductance. A component datasheet lists inductance in millihenries. Convert 2.5 H to mH.

2.5 H × 1,000 = 2,500 mH

3. Motor Winding — Millihenry to Henry

An electric motor winding shows 750 mH of inductance. A power calculation requires the value in henries. Convert 750 mH to H.

750 mH ÷ 1,000 = 0.75 H

Quick Reference Table

Common real-world inductance values, for quick lookup without re-entering numbers.

Value	In Henries	Common Use
10 nH	0.00000001	PCB trace inductance / RF layout
100 nH	0.0000001	Small RF chip inductor
1 µH	0.000001	RF choke / small signal inductor
150 µH	0.00015	AM/FM radio antenna coil
3.3 mH	0.0033	Speaker crossover inductor
10 mH	0.01	Small power-supply choke
750 mH	0.75	Electric motor winding
2.5 H	2.5	Power-supply transformer primary
1 abH	0.000000001	CGS-EMU legacy reference (= 1 nH)

Frequently Asked Questions

How many millihenries are in 1 henry?

1 henry equals 1,000 millihenries. Multiply a henry value by 1,000 to get millihenries, or divide a millihenry value by 1,000 to get henries.

What is an abhenry, and why is it the same size as a nanohenry?

The abhenry is the unit of inductance from the older CGS-EMU (centimeter-gram-second, electromagnetic) system. By definition, 1 abhenry equals exactly 1×10⁻⁹ henry — the same magnitude as a nanohenry — which is why the two units coincide numerically even though they come from different measurement systems.

What is a stathenry used for?

The stathenry is the unit of inductance from the CGS-ESU (electrostatic) system. It equals approximately 8.9876 × 10¹¹ henries — an enormous value — because it's derived using the speed of light as a conversion constant between the ESU and SI systems. It appears almost exclusively in historical texts and theoretical physics, not in practical electronics. See the Guide to Inductance Units above for more detail.

What's the difference between henries and weber-per-ampere?

There is no difference in size — they're the same unit under two names. The henry is defined as one weber of magnetic flux linkage per ampere of current (1 H = 1 Wb/A), so a value in Wb/A converts to henries at a 1:1 ratio. Wb/A is simply the flux-linkage form of the definition, sometimes used in physics contexts.

How do I calculate inductive reactance from an inductance value?

Inductive reactance is X_L = 2πfL, where f is frequency in hertz and L is inductance in henries. Enter your inductance above, then use the Inductive Reactance quick calculator below the results to enter a frequency and get X_L in ohms.

How do I calculate the energy stored in an inductor?

The energy stored in an inductor's magnetic field is E = ½LI², where L is inductance in henries and I is current in amps. Enter your inductance above, then use the Energy Stored quick calculator below the results to enter a current and get the energy in joules.

Inductance Converter

How to Use the Inductance Converter

Guide to Inductance Units Comprehensive Guide

SI-Prefixed Units (Picohenry through Kilohenry)

Legacy CGS Units — Abhenry & Stathenry

Weber per Ampere (Wb/A)

Inductive Reactance (XL = 2πfL)

Energy Stored (E = ½LI²)

Custom Unit

Worked Examples

Quick Reference Table

Frequently Asked Questions

How many millihenries are in 1 henry?

What is an abhenry, and why is it the same size as a nanohenry?

What is a stathenry used for?

What's the difference between henries and weber-per-ampere?

How do I calculate inductive reactance from an inductance value?

How do I calculate the energy stored in an inductor?

Related Electrical Calculators

Inductive Reactance (X_L = 2πfL)