SI Henry Units
Picohenry
pH
Nanohenry
nH
Microhenry
µH
Millihenry
mH
Henry
H
Kilohenry
kH
Legacy CGS & Derived Units
Abhenry
abH
Stathenry
statH
Weber / Ampere
Wb/A
Formula: —
Quick Calculators
Inductive Reactance
Enter a frequency to find XL for the inductance value above.
XL = 2πfL
Energy Stored
Enter a current to find the energy stored in the magnetic field.
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.

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

Value In Henries Common Use
10 nH0.00000001PCB trace inductance / RF layout
100 nH0.0000001Small RF chip inductor
1 µH0.000001RF choke / small signal inductor
150 µH0.00015AM/FM radio antenna coil
3.3 mH0.0033Speaker crossover inductor
10 mH0.01Small power-supply choke
750 mH0.75Electric motor winding
2.5 H2.5Power-supply transformer primary
1 abH0.000000001CGS-EMU legacy reference (= 1 nH)

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

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 (XL = 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 XL 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.