Convert Microinch to Nail
Convert microinches to nails instantly. 1 microinch = 4.444444e-7 nail — use the live calculator, the exact formula, a conversion table and worked examples. Also check the Nail to Microinch converter for the reverse conversion.
Units explained
Microinch
A microinch is an Imperial unit of length equal to one millionth of an inch (2.54×10⁻⁸ m). It is used almost exclusively in surface-finish specifications for precision machining and optical components.
The microinch is derived from the inch using the SI-style prefix micro- to denote one millionth. Standardised through the 1959 International Yard and Pound Agreement, which fixed the inch at exactly 25.4 mm.
Microinches express surface roughness (Ra values) in US-based precision manufacturing — typical machined surfaces are 16–125 µin. Optical components and bearing races are often specified to 1–4 µin Ra.
Used in US precision-manufacturing literature throughout the 20th century; value became exact in 1959 when the inch was fixed at 25.4 mm via the International Yard and Pound Agreement.
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.
Microinch to Nail conversion formula
The relationship between microinches and nails:
To convert microinches to nails, multiply the value in microinches by 4.444444e-7. To reverse, multiply nails by 2250000.
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 Microinch converter for the reverse direction.
Step-by-step: convert microinches to nails
- Write down the value in microinches (µin).
- Multiply that value by the factor 4.444444e-7.
- The product is the equivalent value in nails (nail).
- To reverse, multiply the nail value by 2250000.
Worked examples
Example 1 — Convert 1 µin to nail:
1 × 4.444444e-7 = 4.444444e-7 nail
Example 2 — Convert 100 µin to nail:
100 × 4.444444e-7 = 4.444444e-5 nail
Real-world example — From wavelengths to millimeter-scale objects
A value of one million microinches sounds vast at the atomic scale but converts to a small everyday quantity in nails — useful when relating optical-wavelength specifications to physical mounting hardware.
1000000 µin × 4.444444e-7 = 0.4444444444 nail
Real-world example — Sub-micron to millimeter
500,000 microinches converts to a small everyday quantity in nails — useful when relating optical-wavelength specifications to physical mounting hardware.
500000 µin × 4.444444e-7 = 0.2222222222 nail
Microinch to Nail conversion table
Standard reference values for converting microinches to nails:
| Microinch [µin] | Nail [nail] |
|---|---|
| 0.01 | 4.444444e-9 |
| 0.1 | 4.444444e-8 |
| 1 | 4.444444e-7 |
| 2 | 8.888889e-7 |
| 3 | 1.333333e-6 |
| 4 | 1.777778e-6 |
| 5 | 2.222222e-6 |
| 10 | 4.444444e-6 |
| 20 | 8.888889e-6 |
| 30 | 1.333333e-5 |
| 40 | 1.777778e-5 |
| 50 | 2.222222e-5 |
| 100 | 4.444444e-5 |
| 500 | 0.0002222222 |
| 1000 | 0.0004444444 |
Frequently asked questions
How many nails is 1 microinch?
How do I convert microinches to nails?
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How many nails is 100 microinches?
Popular length unit conversions
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Metric / SI (4 units)
Imperial / US Customary (26 units)
Sources & references
Conversion factor (1 µin = 4.444444e-7 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 Hydrographic Organization — Resolution on the Nautical Mile
International authority that standardised the nautical mile at exactly 1852 m in 1929 — the value adopted worldwide for sea and air navigation.