Convert between nautical miles, statute miles, kilometers, and knots. Calculate travel time, fuel consumption, and distances for maritime and aviation use.
The Nautical Mile Calculator converts between nautical miles, statute miles, kilometers, and meters for maritime and aviation applications. A nautical mile equals one minute of latitude (1/60th of a degree), making it fundamental to navigation since it directly relates to Earth's coordinate system.
This tool handles distance conversions, speed calculations (knots to mph/kph), travel time estimates, and fuel consumption planning. Whether you're plotting a sailing course, filing a flight plan, or studying for a navigation exam, the calculator provides instant, accurate conversions with explanations of the underlying relationships.
The calculator also includes great circle distance computation between two coordinate points, Beaufort scale wind speed references, and conversion tables for common maritime and aviation distances. Understanding nautical measurements is essential for anyone involved in marine or air transportation, from recreational boaters to commercial pilots. It gives you one place to translate between navigation units without reaching for separate conversion charts quickly.
Use this calculator when distance, speed, and time all need to stay in nautical units. It is helpful for route planning, ETA estimates, fuel planning, and chart work because it keeps the knot-to-mph and nautical-mile-to-statute-mile conversions explicit instead of forcing you to do them by hand. That is especially handy when you are comparing sea routes with land-based distances.
1 Nautical Mile = 1.15078 Statute Miles = 1.852 Kilometers; 1 Knot = 1 NM/hr = 1.15078 mph = 1.852 km/h; Great Circle Distance = R × arccos(sin φ₁ sin φ₂ + cos φ₁ cos φ₂ cos Δλ)
Result: 115.08 mi / 185.2 km, Travel time: 5h 0m
100 nautical miles equals 115.08 statute miles or 185.2 kilometers. At 20 knots, the journey takes exactly 5 hours.
The nautical mile has been used in navigation since the age of sail, originally defined as one minute of arc along a meridian of the Earth. Because Earth is not a perfect sphere (it's an oblate spheroid), this distance actually varies from about 1,843 meters at the equator to 1,862 meters at the poles. In 1929, the international nautical mile was standardized at exactly 1,852 meters.
The knot as a unit of speed dates to the 17th century, when sailors measured their vessel's speed using a "chip log" — a wooden panel attached to a rope with knots tied at regular intervals. The rope was tossed overboard and the number of knots that passed through a sailor's hands in a set time gave the ship's speed in knots.
Today, nautical miles and knots are the international standard for air and sea navigation. Air traffic control separates aircraft by nautical miles, weather reports use knots for wind speed, and maritime charts are scaled in nautical miles. This uniformity ensures safe operations across international boundaries and between different languages and measurement systems.
Nautical miles are directly tied to Earth's latitude lines — one nautical mile equals one minute of latitude. This makes chart navigation much simpler since you can measure distances directly from the latitude scale on any nautical chart. It also keeps distance and latitude changes in the same unit system. That is why the unit is still standard on marine charts.
One knot equals one nautical mile per hour, which is 1.15078 mph or 1.852 km/h. The name comes from the historical practice of measuring speed by counting knots on a rope trailing behind a ship. Modern GPS still uses the same unit for consistency. It gives mariners one speed unit that matches their distance unit.
Nearly. The international nautical mile is defined as exactly 1,852 meters. A "sea mile" historically referred to one minute of latitude at a specific location, which varies slightly due to Earth's oblate shape. The modern nautical mile is the standardized version.
Yes. Aviation uses nautical miles for distances, knots for speed, and feet for altitude worldwide. This standardization ensures clear communication between pilots and controllers of different nationalities. It also keeps navigation math aligned with charting systems.
Multiply knots by 1.15078 to get mph. So 10 knots ≈ 11.5 mph, 20 knots ≈ 23 mph, and 30 knots ≈ 34.5 mph. The calculator does that conversion automatically so you do not have to remember the factor.
The shortest distance between two points on Earth's surface, following the curvature of the globe. It's always shorter than the straight-line distance shown on a flat map (Mercator projection). That matters on long routes where map projections can be misleading.