Convert Nail to Inch
Convert nails to inches instantly. 1 nail = 2.25 inch — use the live calculator, the exact formula, a conversion table and worked examples. Also check the Inch 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.
Inch
An inch is an Imperial and US customary unit of length defined since 1959 as exactly 25.4 millimeters (0.0254 meters). It is still the standard small unit of length in the United States, the United Kingdom (informally), and a few other countries.
The inch derives from the Roman uncia (one-twelfth of a foot) and survived through Anglo-Saxon and medieval English measurement systems. Various definitions persisted regionally until the 1959 International Yard and Pound Agreement standardized the inch globally as exactly 25.4 mm.
Inches are used in the US and UK for body height, screen sizes (TVs, monitors, phones), tire sizes, plumbing, lumber, paper sizes (US Letter is 8.5 × 11 in), and most consumer product specifications in the United States.
Anglo-Saxon origin (predating 1066); standardized to 25.4 mm exactly by the International Yard and Pound Agreement of 1959, signed by the US, UK, Canada, Australia, New Zealand, and South Africa.
Nail to Inch conversion formula
The relationship between nails and inches:
To convert nails to inches, multiply the value in nails by 2.25. To reverse, multiply inches by 0.4444444444.
How to use this converter
Type a value into the calculator. The result in inches updates as you type. Tap a quick value, copy the result with one click, or use the swap arrow to jump straight to the Inch to Nail converter for the reverse direction.
Step-by-step: convert nails to inches
- Write down the value in nails (nail).
- Multiply that value by the factor 2.25.
- The product is the equivalent value in inches (in).
- To reverse, multiply the inch value by 0.4444444444.
Worked examples
Example 1 — Convert 1 nail to in:
1 × 2.25 = 2.25 in
Example 2 — Convert 100 nail to in:
100 × 2.25 = 225 in
Real-world example — Postcard and small-object dimensions
A postcard is about 5 nails wide. Converting to inches is essential for international postal addressing forms that ask for dimensions in different units across countries.
5 nail × 2.25 = 11.25 in
Real-world example — Ruler-scale measurements
A 30-nail school ruler converts cleanly to inches — useful when buying a desk accessory from a retailer whose product specs use a different unit.
30 nail × 2.25 = 67.5 in
Real-world example — Hardware-scale dimensions
A 10-nail fastener or component is about as long as a thumbnail. Mechanics and DIY enthusiasts convert between nails and inches daily when mixing metric and imperial tools.
10 nail × 2.25 = 22.5 in
Nail to Inch conversion table
Standard reference values for converting nails to inches:
| Nail [nail] | Inch [in] |
|---|---|
| 0.01 | 0.0225 |
| 0.1 | 0.225 |
| 1 | 2.25 |
| 2 | 4.5 |
| 3 | 6.75 |
| 4 | 9 |
| 5 | 11.25 |
| 10 | 22.5 |
| 20 | 45 |
| 30 | 67.5 |
| 40 | 90 |
| 50 | 112.5 |
| 100 | 225 |
| 500 | 1125 |
| 1000 | 2250 |
Frequently asked questions
How many inches is 1 nail?
How do I convert nails to inches?
How do I convert inches back to nails?
How many inches 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 = 2.25 in) 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.