Convert Nail to Microinch
Convert nails to microinches instantly. 1 nail = 2250000 microinch — use the live calculator, the exact formula, a conversion table and worked examples. Also check the Microinch to Nail converter for the reverse conversion.
Units explained
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
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 to Microinch conversion formula
The relationship between nails and microinches:
To convert nails to microinches, multiply the value in nails by 2250000. To reverse, multiply microinches by 4.444444e-7.
How to use this converter
Type a value into the calculator. The result in microinches updates as you type. Tap a quick value, copy the result with one click, or use the swap arrow to jump straight to the Microinch to Nail converter for the reverse direction.
Step-by-step: convert nails to microinches
- Write down the value in nails (nail).
- Multiply that value by the factor 2250000.
- The product is the equivalent value in microinches (µin).
- To reverse, multiply the microinch value by 4.444444e-7.
Worked examples
Example 1 — Convert 1 nail to µin:
1 × 2250000 = 2250000 µin
Example 2 — Convert 100 nail to µin:
100 × 2250000 = 2.25e+8 µin
Real-world example — Small-scale to atomic-scale
One nail equals 10 million microinches — useful for physics curricula that relate everyday measurements to atomic and optical scales.
1 nail × 2250000 = 2250000 µin
Real-world example — Centimeter to wavelength scale
One nail equals 10 million microinches. Physics curricula use this kind of conversion to relate everyday measurements to atomic and optical scales.
1 nail × 2250000 = 2250000 µin
Nail to Microinch conversion table
Standard reference values for converting nails to microinches:
| Nail [nail] | Microinch [µin] |
|---|---|
| 0.01 | 22500 |
| 0.1 | 225000 |
| 1 | 2250000 |
| 2 | 4500000 |
| 3 | 6750000 |
| 4 | 9000000 |
| 5 | 1.125e+7 |
| 10 | 2.25e+7 |
| 20 | 4.5e+7 |
| 30 | 6.75e+7 |
| 40 | 9e+7 |
| 50 | 1.125e+8 |
| 100 | 2.25e+8 |
| 500 | 1.125e+9 |
| 1000 | 2.25e+9 |
Frequently asked questions
How many microinches is 1 nail?
How do I convert nails to microinches?
How do I convert microinches back to nails?
How many microinches is 100 nails?
Popular length unit conversions
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Metric / SI (4 units)
Imperial / US Customary (26 units)
Sources & references
Conversion factor (1 nail = 2250000 µin) 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.