Aviation conversions

What this converter includes

The converter handles common aviation units for distance, speed, altitude, mass, fuel volume, pressure, and temperature. Choose a measurement, enter a value, then select its starting and target units. The result updates immediately and the selections are mirrored in the page URL.

Available units include nautical and statute miles, kilometers, feet, meters, knots, miles per hour, kilometers per hour, meters per second, pounds, kilograms, US gallons, liters, inches of mercury, hectopascals, Celsius, and Fahrenheit.

How to use the converter

Select the quantity before choosing units. Changing the quantity resets the unit pair to the first two units in that group. Negative values are supported where they are meaningful, such as temperature; all outputs are shown to at most six decimal places.

Check the labels before using a result. A nautical mile and a statute mile are different lengths. A US gallon differs from an imperial gallon, and this tool converts only US gallons. Altitude conversions express a length only; they do not convert pressure altitude, density altitude, or a flight level.

Conversion method

Linear conversions use a base unit and exact or commonly adopted unit factors. For example, one nautical mile is 1,852 meters, and one knot is one nautical mile per hour. Temperature uses an offset as well as a scale factor because zero degrees Fahrenheit and zero degrees Celsius do not share the same zero point.

For a linear unit, the converter first multiplies the input by its factor to reach a base unit, then divides by the target unit's factor. Temperature applies its offset during those steps.

Worked examples

Distance. One nautical mile is exactly 1.852 kilometers, so 1 NM converts to 1.852 km.

Speed. One knot is one nautical mile per hour. Since one nautical mile is 1,852 meters, 100 kt is about 185.2 km/h or 115.1 mph.

Temperature. To convert Fahrenheit to Celsius, subtract 32 and multiply by five ninths. A temperature of 68°F is 20°C.

Fuel volume. One US gallon is approximately 3.7854 L. This is a volume conversion; it does not calculate usable fuel, fuel mass, or fuel required for a flight.

When pilots use unit conversions

Conversions are useful when a training problem, chart, aircraft document, or weather reference uses a different unit from the one a pilot expects. A student might compare a distance in nautical miles with a document in kilometers, convert a temperature before working a problem, or compare pounds with kilograms in a loading exercise.

Convert only values that describe the same kind of quantity. A distance conversion cannot translate a flight level into height above ground, and a temperature conversion cannot substitute for a pressure or density calculation. A number may be correctly converted and still be inappropriate for the intended aviation task.

Common unit mix-ups

Nautical miles are used for many aviation distances; statute miles are commonly used for visibility and some United States references. The abbreviations NM, mi, and SM are not interchangeable. This converter labels statute miles as mi, so check the category and label rather than relying on the number alone.

Pressure units can also be confused with altitude units. Converting inches of mercury to hectopascals changes the expression of pressure, not the altimeter setting's meaning or the altitude indicated by a particular instrument. Always retain the source, setting, and reference information alongside a converted value.

Aviation use and limitations

Pilots and students encounter mixed units in charts, weather products, aircraft documents, and training problems. A conversion can help compare values that describe the same physical quantity, but it cannot reconcile different references or assumptions. For example, converting feet to meters does not make two altitudes equivalent if one is pressure altitude and the other is height above ground.

The pounds-to-kilograms option is a mass conversion. Aircraft documents often express loading in pounds as weight, but the calculator does not include gravity, aircraft station arms, moments, or center of gravity. Use the applicable aircraft loading data for weight-and-balance work.

Displayed results are rounded to at most six decimal places. Calculations retain more precision internally, but displayed precision may not be suitable for every technical application. Confirm required precision and units in the source document.

Sources and methodology

Unit definitions follow established SI and US customary values. The National Institute of Standards and Technology SI reference describes SI units and prefixes. Nautical-mile and knot definitions are used as standard aviation relationships. This page is a unit converter, not an aviation performance calculator.

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