Unit converter

Speed converter

Convert kilometers per hour, miles per hour, knots, and other speed units.

Enter a value and choose units. Results update instantly.

1 km/h = 0.6213711922 mph

All Speed units

From 1 km/h
UnitValue
Meter per second m/s 0.2777777778
Kilometer per hour km/h 1
Mile per hour mph 0.6213711922
Knot kn 0.5399568035
Foot per second ft/s 0.9113444153
Centimeter per second cm/s 27.7777777778
Speed of light c 0.0000000009
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Common tasks

Kilometer per hour to Mile per hourkm/h to mph Mile per hour to Kilometer per hourmph to km/h Knot to Kilometer per hourkn to km/h Meter per second to Kilometer per hourm/s to km/h Mile per hour to Meter per secondmph to m/s Knot to Mile per hourkn to mph

Reference

How speed conversion works

Speed is distance traveled per unit of time. Fixed units convert through meters per second; Mach is excluded because its value depends on temperature and the medium.

Values are converted to meter per second first, then from that reference into the requested unit. Keeping a single documented reference reduces inconsistent pair-by-pair constants.

Accuracy note: All listed factors are fixed by exact length and time definitions.

Unit reference

UnitSymbol1 unit in m/s
Meter per secondm/s1
Kilometer per hourkm/h0.277777777778
Mile per hourmph0.44704
Knotkn0.514444444444
Foot per secondft/s0.3048
Centimeter per secondcm/s0.01
Speed of lightc299,792,458

Long-tail directory

Every indexed conversion

Choose a source unit to see all available destinations.

From Meter per second (m/s)
Meter per second to Kilometer per hourMeter per second to Mile per hourMeter per second to KnotMeter per second to Foot per secondMeter per second to Centimeter per secondMeter per second to Speed of light
From Kilometer per hour (km/h)
Kilometer per hour to Meter per secondKilometer per hour to Mile per hourKilometer per hour to KnotKilometer per hour to Foot per secondKilometer per hour to Centimeter per secondKilometer per hour to Speed of light
From Mile per hour (mph)
Mile per hour to Meter per secondMile per hour to Kilometer per hourMile per hour to KnotMile per hour to Foot per secondMile per hour to Centimeter per secondMile per hour to Speed of light
From Knot (kn)
Knot to Meter per secondKnot to Kilometer per hourKnot to Mile per hourKnot to Foot per secondKnot to Centimeter per secondKnot to Speed of light
From Foot per second (ft/s)
Foot per second to Meter per secondFoot per second to Kilometer per hourFoot per second to Mile per hourFoot per second to KnotFoot per second to Centimeter per secondFoot per second to Speed of light
From Centimeter per second (cm/s)
Centimeter per second to Meter per secondCentimeter per second to Kilometer per hourCentimeter per second to Mile per hourCentimeter per second to KnotCentimeter per second to Foot per secondCentimeter per second to Speed of light
From Speed of light (c)
Speed of light to Meter per secondSpeed of light to Kilometer per hourSpeed of light to Mile per hourSpeed of light to KnotSpeed of light to Foot per secondSpeed of light to Centimeter per second

Primary source

Definitions and standards

Conversion constants and definitions for this category are checked against BIPM SI Brochure and international unit definitions.

See Methods & sources for rounding rules, exact-value handling, and review policy.

Questions

Speed FAQ

What is the reference unit for speed conversions?

ConvertWin uses meter per second (m/s) as the internal reference for this category, then converts to the selected output unit.

How accurate is this speed converter?

All listed factors are fixed by exact length and time definitions.