Convert Mil to Nail
Convert mils to nails instantly. 1 mil = 0.0004444444 nail — use the live calculator, the exact formula, a conversion table and worked examples. Also check the Nail to Mil converter for the reverse conversion.
Units explained
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.
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.
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.
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".
Nail
A nail is an Imperial unit of length equal to 2.25 inches (about 57.15 mm). It was historically used in the English cloth trade.
The nail derives from an English cloth-measure tradition dating to medieval times. Standardised at 2.25 inches (or 1/16 of a yard) through English customary practice and ratified by the 1959 International Yard and Pound Agreement.
Nails were historically used to measure cloth, particularly small pieces and ribbons. Rare in modern commerce but appears in historical textile literature and reproduction crafts.
Medieval English cloth-trade origin; standardised at 1/16 yard; fixed exactly at 0.05715 m via the 1959 International Yard and Pound Agreement.
Mil to Nail conversion formula
The relationship between mils and nails:
To convert mils to nails, multiply the value in mils by 0.0004444444. To reverse, multiply nails by 2250.
How to use this converter
Type a value into the calculator. The result in nails updates as you type. Tap a quick value, copy the result with one click, or use the swap arrow to jump straight to the Nail to Mil converter for the reverse direction.
Step-by-step: convert mils to nails
- Write down the value in mils (mil).
- Multiply that value by the factor 0.0004444444.
- The product is the equivalent value in nails (nail).
- To reverse, multiply the nail value by 2250.
Worked examples
Example 1 — Convert 1 mil to nail:
1 × 0.0004444444 = 0.0004444444 nail
Example 2 — Convert 100 mil to nail:
100 × 0.0004444444 = 0.0444444444 nail
Real-world example — Packaging gauge
A 4-mil plastic bag thickness is a common spec for grocery and freezer bags. Converting from mils to nails is what packaging buyers do whenever they bridge US and metric supplier quotes.
4 mil × 0.0004444444 = 0.0017777778 nail
Real-world example — Plastic film and laminate thickness
A 500-mil sheet is a typical spec for ID-card laminates and film overlays. Converting to nails aligns the value with the unit most CAD systems and material datasheets prefer.
500 mil × 0.0004444444 = 0.2222222222 nail
Mil to Nail conversion table
Standard reference values for converting mils to nails:
| Mil [mil] | Nail [nail] |
|---|---|
| 0.01 | 4.444444e-6 |
| 0.1 | 4.444444e-5 |
| 1 | 0.0004444444 |
| 2 | 0.0008888889 |
| 3 | 0.0013333333 |
| 4 | 0.0017777778 |
| 5 | 0.0022222222 |
| 10 | 0.0044444444 |
| 20 | 0.0088888889 |
| 30 | 0.0133333333 |
| 40 | 0.0177777778 |
| 50 | 0.0222222222 |
| 100 | 0.0444444444 |
| 500 | 0.2222222222 |
| 1000 | 0.4444444444 |
Frequently asked questions
How many nails is 1 mil?
How do I convert mils to nails?
How do I convert nails back to mils?
How many nails is 100 mils?
Popular length unit conversions
Convert Mil to other length units
Show all Mil conversions
Metric / SI (7 units)
Imperial / US Customary (26 units)
Nautical (1 units)
Sources & references
Conversion factor (1 mil = 0.0004444444 nail) verified against the following authoritative sources:
- BIPM — The International System of Units (SI Brochure 9th ed.)
Official BIPM publication defining the seven SI base units (including the meter) and the rules for their use. The global authority on units of measurement.
- NIST — Guide to the SI
US National Institute of Standards and Technology reference covering the SI base and derived units with definitions and usage rules for US technical practice.
- NIST Special Publication 811 — Guide for the Use of the International System of Units
Detailed NIST guide covering exact conversion factors between SI and US customary units along with formatting and rounding conventions.
- NIST — Refinement of values for the yard and pound (Federal Register 1959)
The treaty (signed by US
- International Astronomical Union — System of Astronomical Constants
The IAU defines astronomical units including the AU (149597870700 m exactly) light-year and parsec used in astronomy and astrophysics.