Speed Converter
The Speed Converter switches between kilometers per hour, miles per hour, meters per second, knots and feet per second — useful for driving, aviation, sports and physics. Select the units and see the result live.
What this means
Speed is distance per unit of time. Converting speeds combines the length conversion with the time conversion: 1 mph means 1 mile per hour, so in meters per second it is 1609.344 m ÷ 3600 s ≈ 0.447 m/s.
How we calculate it
Formula
Result = Value × (factor of source unit) ÷ (factor of target unit), all defined exactly against the meter per second.Worked example
Convert 100 km/h to mph:
- 11 km/h = 1000 m ÷ 3600 s = 0.27778 m/s
- 21 mph = 0.44704 m/s
- 3100 km/h ≈ 62.14 mph
Important assumptions
- Uses the exact international definitions (1 mile = 1,609.344 m; 1 knot = 1,852 m per hour).
Frequently asked questions
How fast is 100 km/h in mph?
100 km/h ≈ 62.14 mph. Multiply km/h by 0.621371.
How many knots is 1 mph?
1 mph ≈ 0.868976 knots. Knots are used in maritime and aviation.
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