Convert Inch to Nautical Mile
Convert inches to nautical miles instantly. 1 inch = 1.37149e-5 nautical mile — use the live calculator, the exact formula, a conversion table and worked examples. Also check the Nautical Mile to Inch converter for the reverse conversion.
Units explained
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.
Nautical Mile
A nautical mile is a unit of length equal to exactly 1,852 meters, defined as one minute of arc along any meridian of the Earth. It is the standard unit for sea and air navigation worldwide.
Originally defined as one minute of arc along a great circle of the Earth, making it convenient for celestial navigation. The International Hydrographic Organization (IHO) standardized the value at exactly 1,852 meters in 1929.
Nautical miles are used in maritime navigation, aviation, and international law (territorial waters, exclusive economic zones). Speed in nautical miles per hour is called a knot. The nautical mile is distinct from the statute (land) mile.
Defined for celestial navigation since antiquity; standardized to 1,852 m exactly by the IHO in 1929; adopted by the International Civil Aviation Organization (ICAO) for aviation use.
Inch to Nautical Mile conversion formula
The relationship between inches and nautical miles:
To convert inches to nautical miles, multiply the value in inches by 1.37149e-5. To reverse, multiply nautical miles by 72913.3858267717.
How to use this converter
Type a value into the calculator. The result in nautical miles updates as you type. Tap a quick value, copy the result with one click, or use the swap arrow to jump straight to the Nautical Mile to Inch converter for the reverse direction.
Step-by-step: convert inches to nautical miles
- Write down the value in inches (in).
- Multiply that value by the factor 1.37149e-5.
- The product is the equivalent value in nautical miles (nmi).
- To reverse, multiply the nautical mile value by 72913.3858267717.
Worked examples
Example 1 — Convert 1 in to nmi:
1 × 1.37149e-5 = 1.37149e-5 nmi
Example 2 — Convert 100 in to nmi:
100 × 1.37149e-5 = 0.0013714903 nmi
Real-world example — Small to geographic-scale
100,000 inches equals one nautical mile — a useful conversion when small-scale survey diagrams must be related to road-network distances on a different map.
100000 in × 1.37149e-5 = 1.3714902808 nmi
Real-world example — Architectural to geographic scale
A 100,000-inch measurement equals one nautical mile. The five-order-of-magnitude scale change comes up in mapping work where architectural site plans must be related to road-network maps.
100000 in × 1.37149e-5 = 1.3714902808 nmi
Inch to Nautical Mile conversion table
Standard reference values for converting inches to nautical miles:
| Inch [in] | Nautical Mile [nmi] |
|---|---|
| 0.01 | 1.37149e-7 |
| 0.1 | 1.37149e-6 |
| 1 | 1.37149e-5 |
| 2 | 2.742981e-5 |
| 3 | 4.114471e-5 |
| 4 | 5.485961e-5 |
| 5 | 6.857451e-5 |
| 10 | 0.000137149 |
| 20 | 0.0002742981 |
| 30 | 0.0004114471 |
| 40 | 0.0005485961 |
| 50 | 0.0006857451 |
| 100 | 0.0013714903 |
| 500 | 0.0068574514 |
| 1000 | 0.0137149028 |
Frequently asked questions
How many nautical miles is 1 inch?
How do I convert inches to nautical miles?
How do I convert nautical miles back to inches?
How many nautical miles is 100 inches?
Popular length unit conversions
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Metric / SI (18 units)
Imperial / US Customary (26 units)
Nautical (1 units)
Astronomical (9 units)
Atomic / Physics (6 units)
Typographic (3 units)
Sources & references
Conversion factor (1 in = 1.37149e-5 nmi) 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.