Speed Converter
Enter a speed in any unit to see it in the others, including knots used at sea and in the air, and Mach for aircraft.
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Speed table
Ejemplos resueltos
Knots into kilometres per hour
10 knots
18.52 km/h.
A knot is one nautical mile per hour, and one nautical mile is 1.852 km.
Km/h into miles per hour
100 km/h
About 62.14 mph.
Dividing by 1.609344 gives the miles per hour figure, which is how speed limits are compared across the two systems.
Sobre Speed Converter
Speed is quoted in different units depending on where you are and what you are measuring. Road signs and speedometers in the UK use miles per hour, most of the world uses kilometres per hour, science often uses metres per second, and pilots and sailors use knots. Mach is used for aircraft that fly near the speed of sound. This speed converter takes a value in any of these units and shows it in all the others, so a figure from a manual, a forecast or a race report can be read in the unit you know best.
Below the converter is a speed table with common values from 10 to 100 miles per hour, showing the same speed in kilometres per hour, metres per second, knots and Mach. The Mach figure uses the speed of sound at sea level and 15 °C, which is about 340 metres per second. Sound travels more slowly in colder air and faster in warmer air, so the Mach value shown is an approximate guide for everyday use rather than an exact figure for every flight.
Cómo usar Speed Converter
- Type a speed into the speed box and choose its unit, such as miles per hour or knots.
- Read the table below the result to see the same speed in the other units.
- Use the speed table to compare common speeds without typing anything in.
- For aircraft, read the Mach figure as an approximate guide, since the speed of sound changes with height and temperature.
- Copy the result if you want to keep the figures for a trip or a report.
Usos habituales
- Converting a motorway speed limit into kilometres per hour before driving abroad
- Checking a wind speed given in knots against a forecast in metres per second
- Reading a flight speed quoted in Mach as a figure in miles per hour
- Comparing running and cycling speeds from different sources
Preguntas frecuentes
How many km/h is 60 mph?
Sixty miles per hour is about 96.6 kilometres per hour. One mile is 1.609344 kilometres, so the sum is 60 times 1.609344. This is a useful figure to remember when driving abroad, where speed limits are shown in kilometres per hour. The converter gives the same figure with more decimal places if you need them.
What is a knot?
A knot is one nautical mile per hour, and a nautical mile is 1,852 metres. Knots are used at sea and in the air because a nautical mile matches one minute of latitude on a chart, which makes navigation sums simpler. One knot is about 1.15 miles per hour, so a speed of 10 knots is about 11.5 miles per hour. The converter handles this for you in either direction.
What is Mach 1?
Mach 1 is the speed of sound in the surrounding air. At sea level and 15 °C it is about 340 metres per second, or about 1,225 kilometres per hour. Because sound travels more slowly in colder air, the same Mach number is a lower real speed at high altitude. Aircraft quote Mach numbers, so the converter gives an approximate figure for them in the other units.
How fast is a metre per second in mph?
One metre per second is about 2.24 miles per hour. It is the standard unit in physics and many science lessons, because it works neatly with other measurements. The conversion is simple: multiply metres per second by 3.6 to get kilometres per hour, then by 0.621 to get miles per hour. The converter does this automatically, so you can type a figure in either unit.
Why do speed limits differ between countries?
Speed limits reflect each country's roads, traffic and local choices, rather than a shared standard. The UK and US use miles per hour, while most other countries use kilometres per hour. A limit of 60 mph is roughly 100 km/h, and the converter helps you check the figures when you travel or read a road sign in another country.