Length · Unit Converter

Convert Nanometer to Mil

Convert nanometers to mils instantly. 1 nanometer = 3.937008e-5 mil — use the live calculator, the exact formula, a conversion table and worked examples. Also check the Mil to Nanometer converter for the reverse conversion.

Written by Sunith Babu L, Ph.D., Lead Engineer Reviewed by Girish V Kulkarni Ph.D.
Length category 2 min read Published Last reviewed Updated

Units explained

Metric / SI

Nanometer

What is a nanometer?

A nanometer is a metric unit of length equal to one billionth of a meter (1×10⁻⁹ m). It is the standard unit for measuring atomic and molecular dimensions and is widely used in physics, chemistry, and electronics.

Origin of the nanometer

Defined using the SI prefix nano- (from Greek nanos, "dwarf") to denote one-billionth, adopted by the General Conference on Weights and Measures (CGPM) in 1960.

Where it is used

Nanometers are used to measure wavelengths of visible light (400–700 nm), semiconductor transistor sizes (currently 3–5 nm process nodes), DNA double helix width (2 nm), and atomic radii. The 2019 SI redefinition fixed the meter to the speed of light, making nanometer definitions exact to atomic precision.

When and where it was developed

SI prefix nano- adopted by the CGPM in 1960; nanometer became the standard unit for nanotechnology and optical wavelengths during the late 20th century.

Imperial / US Customary

Mil

What is a mil?

A mil (also called a thou) is an Imperial unit of length equal to one thousandth of an inch (1/1000 in = 0.0254 mm = 25.4 μm exactly). It is used in engineering, manufacturing, and materials specifications.

Origin of the mil

The mil is derived from the Latin mille, "thousand," denoting one-thousandth of an inch. Standardized in industrial use during the 19th-century rise of precision engineering.

Where it is used

Mils are used to specify thicknesses of plastic films, foils, paper, copper traces on printed circuit boards (PCBs), wire insulation, and paint coatings. A standard sheet of paper is about 4 mils thick.

When and where it was developed

Adopted in 19th-century engineering practice; the value (1/1000 in) became exact in 1959 when the inch was fixed at 25.4 mm via the International Yard and Pound Agreement. The British term is "thou"; American term is "mil".

Nanometer to Mil conversion formula

The relationship between nanometers and mils:

1 nm = 3.937008e-5 mil
1 mil = 25400 nm

To convert nanometers to mils, multiply the value in nanometers by 3.937008e-5. To reverse, multiply mils by 25400.

How to use this converter

Type a value into the calculator. The result in mils updates as you type. Tap a quick value, copy the result with one click, or use the swap arrow to jump straight to the Mil to Nanometer converter for the reverse direction.

Step-by-step: convert nanometers to mils

  1. Write down the value in nanometers (nm).
  2. Multiply that value by the factor 3.937008e-5.
  3. The product is the equivalent value in mils (mil).
  4. To reverse, multiply the mil value by 25400.

Worked examples

Example 1 — Convert 1 nm to mil:
1 × 3.937008e-5 = 3.937008e-5 mil

Example 2 — Convert 100 nm to mil:
100 × 3.937008e-5 = 0.0039370079 mil

Real-world example — Spanning sub-micron to micron scale

Crossing from nanometers to mils is the everyday workflow of microscopy and semiconductor engineering — a measurement of 1000 nanometers translates to a much more compact value in mils that fits the scale of biological cells and process nodes.

1000 nm × 3.937008e-5 = 0.0393700787 mil

Real-world example — Sub-visible-light wavelength

500 nanometers (the green-yellow visible band) equals 0.5 mils — the canonical conversion in optics between wavelength specifications and micron-scale lens-coating thicknesses.

500 nm × 3.937008e-5 = 0.0196850394 mil

Nanometer to Mil conversion table

Standard reference values for converting nanometers to mils:

Nanometer [nm]Mil [mil]
0.013.937008e-7
0.13.937008e-6
13.937008e-5
27.874016e-5
30.0001181102
40.0001574803
50.0001968504
100.0003937008
200.0007874016
300.0011811024
400.0015748031
500.0019685039
1000.0039370079
5000.0196850394
10000.0393700787

Frequently asked questions

How many mils is 1 nanometer?
1 nanometer equals 3.937008e-5 mil.
How do I convert nanometers to mils?
Multiply the value in nanometers by 3.937008e-5 to get mils.
How do I convert mils back to nanometers?
Multiply the value in mils by 25400, or use the Mil to Nanometer converter.
How many mils is 100 nanometers?
100 nanometers equals 0.0039370079 mils, because 100 × 3.937008e-5 = 0.0039370079.

Convert Nanometer to other length units

Show all Nanometer conversions

Sources & references

Conversion factor (1 nm = 3.937008e-5 mil) verified against the following authoritative sources:

Results are provided for general reference. Verify critical measurements against an authoritative standard.