Speed Converter

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   What’s great about our Speed Converter

   Fast, accurate conversion of speeds that you can see and drag

   • Free
   • Converts kilometers/hour, miles/hour, meters/second and knots instantly
   • Synced sliders and type-in boxes
   • No sign-up
   • No ads
   • Works offline once loaded
   • No daily limit
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   Choose which units to show

   Use the unit names at the top to show or hide each card. Drag a name or a card’s title to rearrange them; your order is remembered in this browser, and Restore puts the original order back.

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   Drag a slider or type a value

   Move any slider, or type a number into its “Type Value” box, and every visible unit updates instantly.

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   Widen the range

   Turn on “Faster Speeds” to widen every slider’s range to cover more extreme values.

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What is Speed?

Speed is how fast something moves: the distance it covers in a unit of time. Cars use kilometers or miles per hour, science uses meters per second, and ships and aircraft use knots. This converter shows the same speed in each of them.

About Kilometers/Hour (km/h)

Kilometers per hour is the standard unit of road speed in most countries, used for speed limits, vehicles and weather reports.

• 1 km/h is about 0.2778 m/s, or 0.6214 mph
• A brisk walk is about 5 km/h
• Motorway limits are commonly 100 to 130 km/h in Europe

About Miles/Hour (mph)

Miles per hour is used for road speeds in the US, the UK and a few other countries.

• 1 mph is exactly 1.609344 km/h, or 0.44704 m/s
• US highway limits are typically 55 to 75 mph
• The UK uses mph on road signs, even though fuel is sold by the liter

About Meters/Second (m/s)

Meters per second is the SI unit of speed. It is the standard in physics, engineering and sports science.

• 1 m/s = 3.6 km/h, or about 2.237 mph
• The fastest sprinters reach about 12 m/s
• Sound travels at about 343 m/s in air at 20 °C

About Knots (kn)

The knot is one nautical mile per hour, used for ships, aircraft and wind speeds. One knot is exactly 1.852 kilometers per hour.

• 1 kn is about 0.5144 m/s, or 1.1508 mph
• A nautical mile is about one minute of latitude
• The name comes from knotted ropes pulled out behind ships to measure speed