Free · Speed conversions

Speed in Metric, Road & Marine Units

Convert speed between metres per second, kilometres per hour, miles per hour, feet per second and knots.

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Calculator inputs

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How to use this calculator

  1. Enter the known values in the units shown. Results update as you type.
  2. Edit a calculated value to solve backwards, or lock a value to hold it fixed.
  3. Use the worked example to check the method. Reset restores the starting fields.

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Formula and method

10 metres per second equal 36 kilometres per hour. Road miles use 1,609.344 metres, while one nautical mile is 1,852 metres; one knot is a nautical mile per hour.

km/h = m/s × 3.6; mph = m/s ÷ 0.44704; knots = m/s × 3600 ÷ 1852

Worked example

Enter these known values and leave the other values blank.

Speed in meters per second
10 m/s
Speed in kilometers per hour
36 km/h
Speed in miles per hour
22.37 mph
Speed in feet per second
32.81 ft/s
Speed in knots
19.44 kn
Speed in other units
3.3356e-8 c

Assumptions and limitations

  • All fields represent the same scalar speed. This does not account for direction, acceleration, current, wind or route length.
  • The speed-of-light option uses 299,792,458 m/s in vacuum. Converting a number to that unit does not imply that a physical object can attain the resulting speed.

Common questions

Are knots the same as miles per hour?

No. A knot uses a nautical mile of 1,852 metres; miles per hour use statute miles of 1,609.344 metres. Keep the distance definition consistent when comparing speeds.

References

The calculation equations, inverse formulas, units, and input rules were imported from this source. Bookify provides the interface and equation solver.

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