Speed Converter
Convert between kilometers per hour, miles per hour, meters per second, knots, and feet per second.
About this tool
Speed limits, weather reports, aviation, sailing, and physics homework all use different speed units. Kilometers per hour dominates road signs worldwide, miles per hour persists in the United States and United Kingdom, meters per second is the scientific standard, and knots rule the sea and sky.
A knot is one nautical mile per hour, and a nautical mile is defined as exactly 1852 meters, one minute of latitude. That definition is why knots survive in navigation: distances on charts and speeds relate directly to coordinates.
Frequently asked questions
What is the km/h to mph shortcut?
Multiply by 0.62, or divide by 1.6. So 100 km/h is about 62 mph.
Why do planes and ships use knots?
One knot equals one minute of latitude per hour, which makes speed and chart distance directly comparable during navigation.