Convert inductance between henries (H), millihenries (mH), microhenries (µH), and nanohenries (nH) using exact SI-prefix factors.
SI Units
H
SI unit of inductance. 1 H = 1 volt-second per ampere (V·s/A).
mH
1 mH = 0.001 H. Common range for power-supply and audio inductors.
µH
1 µH = 10⁻⁶ H = 0.001 mH. Typical for RF chokes and switching converters.
nH
1 nH = 10⁻⁹ H = 0.001 µH. Used for high-frequency and parasitic inductance.
Inductance
Inductance is the property of an electrical conductor that opposes changes in the current flowing through it. When current varies, the surrounding magnetic field changes and induces a voltage that resists the change. The henry (H) is the SI unit of inductance, named after Joseph Henry, who discovered electromagnetic self-inductance in the 1830s.
Units of inductance
Henry (H) — the SI base unit. One henry is defined as the inductance that produces one volt of induced electromotive force when the current changes at one ampere per second (1 H = 1 V·s/A). A full henry is large; it appears mainly in mains filter chokes and large transformers.
Millihenry (mH) — 10⁻³ H. The everyday range for power-supply, audio, and filter inductors. A crossover inductor in a loudspeaker is typically a few millihenries.
Microhenry (µH) — 10⁻⁶ H = 10⁻³ mH. Common for switching-regulator inductors, RF chokes, and matching networks. A buck-converter inductor is often 1–100 µH.
Nanohenry (nH) — 10⁻⁹ H = 10⁻³ µH. Used at high frequencies and for parasitic inductance — the small, unavoidable inductance of PCB traces, bond wires, and component leads.
Conversion factors
From
H
mH
µH
nH
1 H
1
1,000
1,000,000
1,000,000,000
1 mH
0.001
1
1,000
1,000,000
1 µH
0.000001
0.001
1
1,000
1 nH
10⁻⁹
0.000001
0.001
1
Each step down the SI-prefix ladder is a factor of 1,000: 1 H = 10³ mH = 10⁶ µH = 10⁹ nH.
Worked example
Suppose a datasheet lists a switching-regulator inductor as 4.7 mH and you need its value in microhenries and nanohenries for a simulation tool that expects µH.
mH to µH: multiply by 1,000.
4.7 mH × 1,000 = 4,700 µH
µH to nH: multiply by 1,000 again.
4,700 µH × 1,000 = 4,700,000 nH
mH to H: divide by 1,000.
4.7 mH ÷ 1,000 = 0.0047 H
So 4.7 mH = 4,700 µH = 4,700,000 nH = 0.0047 H — the same physical inductance expressed at four scales.
Usage
Enter any value in any field. All other units update automatically. For example, type 10 in the µH field to instantly see 0.01 mH, 0.00001 H, and 10,000 nH.
Frequently Asked Questions (FAQ)
How do you convert mH to µH?
Multiply millihenries by 1,000 to get microhenries: 1 mH = 1,000 µH. This follows directly from the SI prefixes, where milli is 10⁻³ and micro is 10⁻⁶. For example, 4.7 mH = 4,700 µH. To go the other way, divide µH by 1,000 to get mH.
What is a henry and what does it measure?
The henry (H) is the SI unit of electrical inductance, named after the American scientist Joseph Henry. One henry is the inductance of a coil in which a current changing at one ampere per second induces an electromotive force of one volt (1 H = 1 V·s/A).
Inductance describes how strongly a component opposes changes in current by storing energy in a magnetic field. A full henry is a large value, so practical components are usually rated in millihenries, microhenries, or nanohenries.
How do I convert µH to nH?
Multiply microhenries by 1,000 to get nanohenries: 1 µH = 1,000 nH. Micro is 10⁻⁶ and nano is 10⁻⁹, so the factor is 10³. For example, a 2.2 µH inductor equals 2,200 nH. Dividing nH by 1,000 returns the value in µH.
How many microhenries are in one henry?
One henry equals 1,000,000 microhenries (1 H = 10⁶ µH), because micro is 10⁻⁶. It also equals 1,000 mH and 1,000,000,000 nH. So a 0.5 H inductor is 500,000 µH, 500 mH, or 5 × 10⁸ nH.
Disclaimer
Conversions use exact SI-prefix factors: 1 H = 10³ mH = 10⁶ µH = 10⁹ nH. This tool converts units of inductance only and does not account for frequency-dependent effects such as parasitic capacitance or core saturation.
