Statute mile vs. nautical mile: differences and conversions

The quick difference

A statute mile and a nautical mile are different units of distance. They cannot be interchanged using the same factor:

The nautical mile is longer by 0.242656 km, or about 243 meters. One nautical mile is approximately 1.15078 mi.

Important: the kilometers-to-miles converter works with statute miles (mi). It does not accept nautical miles (nmi).

When a road sign, race or land distance simply says “miles,” it normally means statute miles. On nautical charts, sea routes and in air navigation, the context may indicate nautical miles.

What a statute mile is

The statute mile, also called the international mile, is the common unit for road distances in countries such as the United States and the United Kingdom.

Its exact equivalent is:

1 mi = 1.609344 km

For example, a distance of 10 mi is:

10 × 1.609344 = 16.09344 km

This article uses the symbol mi. Conventions can differ between publications, but writing the unit explicitly prevents confusion with a nautical mile.

The guide to converting kilometers to miles explains the formulas and rounding used for statute miles.

What a nautical mile is

A nautical mile is a unit of distance used in maritime and air navigation. Its exact international equivalent is:

1 nmi = 1.852 km = 1852 m

NOAA explains that the unit relates to latitude and longitude: one nautical mile corresponds to one minute of latitude. This relationship makes it practical for charts and geographic positions.

This article uses nmi to distinguish it clearly. Charts, instruments and regulations may use other conventions, such as NM, so always check the legend or system documentation.

Do not enter a nautical-mile value into a calculator configured for statute miles. If you entered 10 nmi as though it were 10 mi, you would obtain 16.09344 km instead of the correct 18.52 km.

Conversion table

The table applies the exact factors separately:

For any other value:

kilometers = statute miles × 1.609344
kilometers = nautical miles × 1.852

The reverse operation also depends on the source unit:

statute miles = kilometers / 1.609344
nautical miles = kilometers / 1.852

As a reference, 100 km is approximately 62.1371 mi or 53.9957 nmi. Both results describe the same distance in different units.

A nautical mile and a knot are not the same

A nautical mile measures distance. A knot measures speed:

1 knot = 1 nautical mile per hour

A vessel traveling at 10 knots covers 10 nmi in one hour if it maintains a constant speed. In kilometers per hour:

10 × 1.852 = 18.52 km/h

It is incorrect to say that a route “measures 10 knots,” because a knot does not measure length. Likewise, 10 nmi alone does not describe speed because no time is specified.

How to choose the correct factor

Identify the context and symbol before converting:

• For roads, cars, athletics and everyday land distances in customary-unit contexts, use the statute mile (mi).
• For sea routes, nautical charts and air navigation, check whether the distance is in nautical miles (nmi).
• A value in knots is a speed, not a distance.
• If a document only says “mile,” check its legend, source or context before choosing a factor.

Using 1.609344 instead of 1.852 creates a difference of about 13.1% from the actual nautical distance. The error grows with the quantity: at 100 units, the two results differ by 24.2656 km.

For more context on how these units relate to the metric system, read kilometers vs. miles.

Convert statute miles to kilometers

If your distance is in mi, use the kilometers and statute miles calculator. Enter the amount, select the conversion direction and choose the required precision.

The calculator uses the statute-mile factor:

1 mi = 1.609344 km

Do not use it for nmi values. To convert a nautical distance manually, multiply the nautical miles by 1.852.

Frequently asked questions

How many kilometers are in a nautical mile?

One international nautical mile equals exactly 1.852 km, or 1852 m.

Is a nautical mile longer than a statute mile?

Yes. A nautical mile is 1.852 km and a statute mile is 1.609344 km. The difference is 0.242656 km, or about 243 m.

What is the difference between a nautical mile and a knot?

A nautical mile (nmi) is a unit of distance. A knot is a unit of speed equal to one nautical mile per hour.

Does the kilometers-to-miles calculator convert nmi?

No. It converts kilometers and statute miles (mi). To convert nautical miles to kilometers, multiply the nmi value by 1.852.

Which mile is used on roads?

In road contexts, “mile” normally means a statute mile (mi). Nautical miles are reserved for maritime and air-navigation contexts.

Sources

1. NIST Guide to the SI, Appendix B.9: Conversion Factors · National Institute of Standards and Technology · Accessed July 28, 2026
2. What is the difference between a nautical mile and a knot? · National Oceanic and Atmospheric Administration · Accessed July 28, 2026