Inductance Converter

This inductance converter changes inductance between henries, millihenries, microhenries, nanohenries, abhenries and stathenries. Each metric step is a factor of 1,000: 1 H = 1,000 mH and 1 mH = 1,000 µH. One abhenry equals 1 nH, while one stathenry is about 8.98755 × 10¹¹ H.

How to use the inductance converter

1. Enter the inductance, for example 2.2 mH.
2. In the inductance converter, choose its unit and the target unit, such as mH to µH.
3. Read the inductance converter result: 2.2 mH = 2,200 µH.

For mH to µH, multiply by 1,000; for µH to H, divide by 1,000,000. For nH to µH, divide by 1,000.

What is inductance?

Inductance is a conductor’s tendency to oppose changes in current by storing energy in a magnetic field. The SI unit is the henry (H); inductors in electronics are typically rated in millihenries (mH) or microhenries (µH).

Conversion formula

The inductance converter stores every unit as a multiple of the base unit, the henry (H). To convert:

value in target unit = value × (factor of source unit ÷ factor of target unit)

where each factor is the size of the unit in henries.

Common inductance conversions

From	To	1 unit equals
henry (H)	millihenry (mH)	1,000 mH
millihenry (mH)	microhenry (µH)	1,000 µH
microhenry (µH)	nanohenry (nH)	1,000 nH

Inductance converter worked example

Convert 25 millihenries to microhenries:

1. Factor of mH = 0.001 H
2. Factor of µH = 1 × 10⁻⁶ H
3. 25 × 0.001 ÷ 1 × 10⁻⁶ = 25,000 µH

Inductance unit reference

Unit	Symbol	Group	Equals (H)
Henry	H	SI	1
Millihenry	mH	SI	0.001
Microhenry	µH	SI	1 × 10−6
Nanohenry	nH	SI	1 × 10−9
Abhenry	abH	CGS-EMU	1 × 10−9
Stathenry	statH	CGS-ESU	898,755,178,737

Reverse factors for each inductance unit

The reference table gives each unit in henrys. To go the other way, divide by that factor; the list below does the division for you.

• Millihenry (mH), SI: 1 mH = 0.001 H, so 1 H = 1,000 mH.
• Microhenry (µH), SI: 1 µH = 1 × 10⁻⁶ H, so 1 H = 1,000,000 µH.
• Nanohenry (nH), SI: 1 nH = 1 × 10⁻⁹ H, so 1 H = 1 × 10⁹ nH.
• Abhenry (abH), CGS-EMU: 1 abH = 1 × 10⁻⁹ H, so 1 H = 1 × 10⁹ abH.
• Stathenry (statH), CGS-ESU: 1 statH = 8.98755 × 10¹¹ H, so 1 H = 1.11265 × 10⁻¹² statH.

Inductive reactance and LC resonance

An inductor’s reactance rises with frequency: X_L = 2πfL. With a capacitor it resonates at f = 1 ÷ (2π√(LC)). Values must be in henries and farads:

L	C	Resonant frequency	X_L at 1 kHz
1 mH	1 µF	5,033 Hz	6.283 Ω
100 µH	100 nF	50.33 kHz	0.6283 Ω
10 µH	100 pF	5.033 MHz	0.06283 Ω

Convert the capacitor with the capacitance converter before using the formula.

Inductor codes and stored energy

Small inductors use a three-digit code in microhenries: two digits and a multiplier, so 101 is 100 µH and 472 is 4,700 µH (4.7 mH). Codes with an R mark the decimal point: 4R7 is 4.7 µH. The energy stored in an inductor is E = ½LI², so 10 mH carrying 2 A holds 0.02 J. For an air-core solenoid, L = μ₀N²A ÷ l, with μ₀ ≈ 1.25663706127 × 10⁻⁶ H/m. Use the electric current converter for the current.

L/R time constant

An inductor and resistor have a time constant τ = L ÷ R. A 10 mH coil with 100 Ω of resistance gives τ = 0.01 ÷ 100 = 0.1 ms, so the current reaches about 63% of its final value in that time. The inductance converter helps put mH, µH and nH into henries first.

At the small end, a straight PCB trace has a rule-of-thumb inductance of about 1 nH per millimeter. That is tiny, but at fast edges it matters, which is why decoupling capacitors sit close to chip pins.

Unit prefixes for inductors run from nH for RF chokes to H for mains filters and old audio chokes.

Related converters and calculators

Related electrical tools:

• Capacitance converter: F, µF, pF
• Electric current converter: A and mA
• Magnetic flux converter: Wb and Mx
• Magnetic flux density converter: tesla and gauss
• Frequency to wavelength converter: Hz to m

Sources

BIPM: SI Brochure; NIST CODATA: Vacuum magnetic permeability.

Questions about this calculator