Speed (velocity)
Speed (velocity) units converter - converts units between metric (kilometres per hour, meters per second and many more), british-american (miles per hour, foot per second and many more), nautical (knots) and some other (machs, speed of light etc.)

Some facts

  • Velocity is a vector size.
  • It specifies the change of the position vector in time. The concept of velocity was formalized with the development of calculus. Since then, the velocity is defined as the position vector derivative with time i.e. v = dr / dt, where v is a velocity vector r position vector and t is a time.
  • In common parlance - when we use the word speed - we normally refer to the scalar size, representing the value of the velocity vector (its "length").
  • The velocity by definition only applies to singl point in time. Sometimes, in order to emphasize this fact (and rule out a possible confusion with the average speed) it is called instantaneous velocity.
  • There is also concept of average velocity, which is ratio of distance to time, in which this distance has been traveled.
  • Average velocity is sometimes colloquially called speed, but it is not a phrase used by physicists.
  • The basic unit of velocity in the SI system is m/s (meters per second).
  • According to Einstein's theory of relativity the highest attainable speed in nature is the speed of light amounting to 299 792 458 m/s.
    • The speed of light constant exists in many physical formulas e.g. equation desribing the equivalence of energy and mass E=mc2.
    • Einstein's special theory of relativity gives a more general sense of the speed of light as limit velocity of energy transport (or otherwise velocity of impact) in the universe..
    • The light is electromagnetic wave with the frequency that is visible to the human eye. However, the speed of light concerns to all of electromagnetic waves and does not depend on their frequency. This means that for example radio or wifi signals are transmited with the speed of light.

  • Other common velocity constants are for example:
    • First cosmic velocity - the smallest horizontal velocity to be given to the body relative to the celestial body attracts them to the body is moved along a closed orbit. In other words, it is the speed needed to became a satellite.
    • Second cosmic velocity - the velocity needed to "break free" from the gravitational attraction of the given orb (for example Earth)..
    • Third cosmic velocity - the initial velocity which a body has to have to leave the Solar System.
    • Fourth cosmic velocity - the initial velocity needed to leave the Milky Way.

How to convert

  • Enter the number to field "value" - enter the NUMBER only, no other words, symbols or unit names. You can use dot (.) or comma (,) to enter fractions.
    Examples:
    • 1000000
    • 123,23
    • 999.99999
  • Find and select your starting unit in field "unit". Some unit calculators have huge number of different units to select from - it's just how complicated our world is...
  • And... you got the result in the table below. You'll find several results for many different units - we show you all results we know at once. Just find the one you're looking for.

Links to external sites (leaving Calculla?)

Ancient version of this site - links

"Calculla v1" version of this calculatorIn December 2016 the Calculla website has been republished using new technologies and all calculators have been rewritten. Old version of the Calculla is still available through this link: v1.calculla.com. We left the version 1 of Calculla untouched for archvial purposes.
Direct link to the old version:

Inputs data - value and unit, which we're going to convert

value
unit
decimals

1 (kilometres per hour) is equal to:

metric

unitsymbolvalue
kilometres per hour
km/h
1
kilometres per minute
km/min
0.016666667
kilometres per second
km/s
0.000277778
metres per hour
m/h
1000
metres per minute
m/min
16.666666667
metres per second
m/s
0.277777778

british-american

unitsymbolvalue
miles per hour
mph
0.621371192
miles per minute
0.010356187
miles per second
mps
0.000172603
foot per hour
fph
3280.83989501
foot per minute
fpm
54.680664917
foot per second
fps
0.911344415
inch per hour
iph
39370.0787402
inch per minute
ipm
656.167979003
inch per second
ips
10.936132983
furlong per fortnight
1670.24576473

other

unitsymbolvalue
speed of light in vacuum
c
9.265669311×10-10
speed of sound in air
0.000807494
mach
M
0.000839208
knot
kn
0.53995727
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