ToolFoxSpeed Converter
Convert speed between kilometres/hour, miles/hour, metres/second and knots.
How it works
Each unit is defined by how many kilometres per hour it equals — km/h is the base unit. Converting multiplies your value by the first unit's km/h equivalent and divides by the second unit's, so km/h, mph, m/s and knots all convert through the same one-line formula.
Example
100 km/h is about 62.1371 mph — a typical highway speed limit compared across countries that use different units. One metre per second is exactly 3.6 km/h, and one knot is exactly 1.852 km/h, the unit sailors and pilots use for speed and wind.
Frequently asked questions
Why is 1 m/s exactly 3.6 km/h?
Because there are 3,600 seconds in an hour and 1,000 metres in a kilometre; 3,600 ÷ 1,000 = 3.6, an exact unit-definition conversion with no rounding.
What is a knot?
A knot is one nautical mile per hour, defined as exactly 1.852 km/h — used in aviation, shipping and meteorology instead of km/h or mph.
Is the mph conversion exact?
Yes — 1 mile is internationally defined as exactly 1.609344 kilometres, so the km/h-to-mph conversion carries no rounding error beyond display precision.
Can I use this for wind speed?
Yes — wind speed is reported in the same units (km/h, mph, m/s or knots depending on the country), and the conversion works identically.
Related tools
Work out how much fuel a trip needs and what it will cost, from distance, mileage and fuel price.
Height ConverterConvert height between centimetres and feet/inches instantly, both ways.
Percentage CalculatorThree percentage tools in one: X% of Y, X as a percentage of Y, and percentage change.