How many millihenries are in one henry?

One henry (H) equals exactly 1000 millihenries (mH). The milli- prefix means one-thousandth, so 1 mH = 0.001 H.

What is inductance measured in?

Inductance is measured in henries (H), named after Joseph Henry. Practical inductors in electronics are often rated in millihenries (mH), microhenries (µH), or nanohenries (nH) because 1 H is a relatively large value.

When would I use millihenries instead of henries?

Millihenries are common for audio-frequency inductors, power supply chokes, and filter coils (roughly 1 mH to 10 H range). Henries appear in mains-frequency transformers and large power-line chokes. Using mH avoids writing small decimals like 0.047 H (= 47 mH).

How do I convert mH back to H?

Divide millihenries by 1000 to get henries. For example, 470 mH ÷ 1000 = 0.47 H. The reverse toggle on this converter handles it automatically.

Is this converter accurate for all values?

Yes — the conversion is exact (multiply by 1000 or divide by 1000). There is no rounding error for integer or decimal inputs within standard floating-point precision.

Henries to Millihenries Converter

Name: Henries to Millihenries Converter
Availability: InStock
Author: Nham Vu

Enter a value in henries and instantly get the equivalent in millihenries (1 H = 1000 mH).

Inductance Converter

Enter a value and choose a direction to convert.

Value in Henries (H)

Quick presets

mH = H × 1000

Result

Enter a value on the left to see the result.

Common Henry → Millihenry Reference

Henries (H)	Millihenries (mH)	Typical Use
0.001 H	1 mH	RF choke, small filter coil
0.01 H	10 mH	Audio crossover inductor
0.047 H	47 mH	Power supply filter choke
0.1 H	100 mH	Low-frequency filter
0.47 H	470 mH	Power line filter inductor
1 H	1000 mH	Transformer primary winding
10 H	10,000 mH	Large mains-frequency choke

Summary

Enter a value in henries and instantly get the equivalent in millihenries (1 H = 1000 mH).

How it works

Enter the inductance value in henries (H) in the input field.
The converter multiplies your value by 1000 to get millihenries.
The result in millihenries (mH) appears instantly.
Use the reverse toggle to convert millihenries back to henries.
Click "Copy" to copy the result to your clipboard.

Use cases

Convert inductor specifications from H to mH for circuit design.
Cross-check component datasheets that use different inductance units.
Verify calculations when designing LC filters or oscillator circuits.
Translate textbook inductance values to bench-measurement units.
Compare inductors rated in henries against coils rated in millihenries.

Frequently Asked Questions

Last updated: 2026-07-23 · Reviewed by Nham Vu