Speed Converter
One kilometer per hour equals 0.621371 miles per hour, and 1 mph is exactly 1.609344 km/h. One knot is 1.852 km/h and 1 m/s is 3.6 km/h. This speed converter switches between m/s, km/h, mph, knots and feet per second instantly, using exact SI definitions.
1 km/h = 0.6213712 mph
How to use the Speed Converter
- Type a speed in the From box. It starts at 100 km/h.
- Choose the From and To units, for example km/h and mph.
- Read the converted speed in the To box, or type there to convert the other way.
- Use the swap button to reverse the units, and the chips to see the speed in every other unit.
Formula
result = value × (from-unit in m/s) ÷ (to-unit in m/s)All units convert through meters per second: 1 km/h = 1/3.6 m/s, 1 mph = 0.44704 m/s, 1 knot = 1,852/3,600 m/s (0.514444) and 1 ft/s = 0.3048 m/s.
Common speed conversions
- 100 km/h = 62.14 mph
- 60 mph = 96.56 km/h
- 1 knot = 1.852 km/h = 1.15078 mph
- 1 m/s = 3.6 km/h = 2.23694 mph
- 1 ft/s = 1.09728 km/h
Where each unit is used
- km/h: road speeds and vehicle specifications in most countries
- mph: road speeds in the United States and the United Kingdom
- m/s: physics, engineering and sports science
- Knots: aviation and maritime navigation
- ft/s: engineering and ballistics in the US
Typical speeds for reference
- Walking: about 5 km/h (3 mph)
- Running: about 10 to 15 km/h
- Cycling: about 20 km/h (12 mph)
- Motorway driving: about 110 to 130 km/h
- Airliner cruise: about 900 km/h (485 knots)
- Speed of sound at sea level: about 1,235 km/h (343 m/s)
Speed Converter questions
How do I convert km/h to mph?
Multiply km/h by 0.621371 to get mph. For example, 100 km/h is 62.14 mph and 50 km/h is 31.07 mph. To go from mph to km/h, multiply by 1.609344, so 70 mph is 112.65 km/h. This is useful when driving abroad, where speed limits use the local unit.
How do knots compare with km/h?
One knot is exactly 1.852 km/h, and 1 km/h is 0.539957 knots. A knot is one nautical mile per hour. Knots are the standard unit for ships and aircraft because nautical miles match the latitude scale on navigation charts. Wind speeds at sea are also usually reported in knots.
How do I convert aircraft speeds from knots?
Multiply knots by 1.852 for km/h or by 1.15078 for mph. For example, 500 knots is 926 km/h or 575 mph. Note that airspeed and ground speed differ because of wind, so convert the figure that matches your purpose. Airliners typically cruise at around 450 to 500 knots.
How do I convert running and sprint speeds to m/s?
Divide km/h by 3.6 to get meters per second, or multiply mph by 0.44704. A 10 km/h jog is 2.78 m/s and a 36 km/h sprint is 10 m/s. Meters per second is the standard unit in sports science and physics.
Should I use km/h or mph for vehicle specifications?
Use the unit of the market you are writing for: km/h for Europe, Asia and most of the world, mph for the United States and the United Kingdom. When comparing specifications from different regions, convert everything to one unit first.
What are the most common speed conversion mistakes?
The most common mistakes are using rounded factors for precise work and confusing knots with miles per hour. A knot is 1.15 mph, not 1 mph. Use the exact factors (1 mph = 1.609344 km/h, 1 knot = 1.852 km/h) and round only the final answer.
How do I work out travel time from speed and distance?
Divide distance by speed after putting both in matching units: time = distance ÷ speed. For example, 240 km at 80 km/h takes 3 hours. If the distance is in miles and the speed in km/h, convert one of them first.