Aviation mixes unit systems freely: distances in nautical miles, speeds in knots, altitudes in feet, fuel in litres or kilograms, and visibility in metres or statute miles depending on the country. This converter handles the standard relationships in one place, using the exact international definitions.
How this calculator works
Conversions use internationally standard unit relationships.
Worked example
500 nautical miles is exactly 926 km, or about 575 statute miles. 150 knots is 278 km/h or 173 mph. 10,000 ft is 3,048 m. The relationships are fixed by definition, so the conversions are exact rather than estimates.
The conversions this page is asked for most
Aviation mixes three measurement systems and the aircraft does not care which one you think in. Distances and speeds are nautical, altitudes are in feet almost everywhere, and fuel and weight arrive in litres and kilograms in Europe and gallons and pounds in the United States. The table converts the values that come up most.
| Value | As nautical miles | As knots | As feet |
|---|---|---|---|
| 100 | 185 km, 115 mi | 185 km/h, 115 mph | 30 m |
| 250 | 463 km, 288 mi | 463 km/h, 288 mph | 76 m |
| 500 | 926 km, 575 mi | 926 km/h, 575 mph | 152 m |
| 750 | 1,389 km, 863 mi | 1,389 km/h, 863 mph | 229 m |
| 1,000 | 1,852 km, 1,151 mi | 1,852 km/h, 1,151 mph | 305 m |
| 1,500 | 2,778 km, 1,726 mi | 2,778 km/h, 1,726 mph | 457 m |
What the table holds fixed
- Distance and speed share a conversion factor, so the first two columns carry the same digits with different units. A nautical mile per hour is a knot, which is the whole reason aviation uses both.
- A nautical mile is one minute of latitude. That is why marine and air navigation both adopted it, and why a chart scale can be read straight off the latitude edge.
- Flight levels are pressure altitudes on the 1013 hPa standard setting, so converting one to metres describes a pressure surface rather than a height above the ground.
Frequently asked questions
Why does aviation use nautical miles and knots?
One nautical mile equals one minute of latitude, which makes distances measurable directly on a chart with dividers, and one knot is simply one nautical mile per hour. The system predates aviation, it was inherited from marine navigation because the geometry works anywhere on Earth.
How long is a nautical mile exactly?
Exactly 1,852 metres by international definition, about 1.151 statute miles. A statute mile is 1,609.344 metres, so the two differ by roughly 15%, which matters when converting visibility or range figures between European and US publications.
Which countries use metres for altitude?
China, Mongolia and parts of Central Asia assign flight levels in metres; Russia moved to feet at higher levels in recent years but kept metric procedures lower down. Everywhere else altimetry runs in feet, which is why cross-border metric conversion remains a live skill for ferry and airline pilots.