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Speed Converter

Convert between mph, km/h, m/s, knots, and ft/s.

Conversion Setup

Enter the value and select the units.

Converted Result
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Calculation Breakdown:

Enter values to convert.

Conversion Details
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About this topic

Metric Speed (km/h & m/s) The standard units of speed in most of the world.

Kilometers per hour (km/h) is the standard for road speed in most countries. Meters per second (m/s) is the SI unit used in physics and science.

Key formulas & rules

  • •1 m/s = 3.6 km/h
  • •1 km/h = 0.2778 m/s
  • •m/s is the SI derived unit
  • •km/h is used for vehicles
  • •m/s is used for wind and physics
  • •Metric is base-10

Examples

Input Output Note
100 km/h 27.78 m/s Divide by 3.6
10 m/s 36 km/h Multiply by 3.6
50 km/h 13.89 m/s City speed
340 m/s 1224 km/h Speed of sound

Real-world uses

Driving Weather (wind speed) Physics problems
Imperial Speed (mph & ft/s) Used primarily in the US and UK.

Miles per hour (mph) measures road speed in the US and UK. Feet per second (ft/s) is often used in engineering and ballistics in the US.

Key formulas & rules

  • •1 mph = 1.609 km/h
  • •1 mph = 0.44704 m/s
  • •1 ft/s = 0.3048 m/s
  • •1 mph = 1.467 ft/s
  • •Used in US/UK traffic
  • •Used in US engineering

Examples

Input Output Note
60 mph 96.56 km/h Highway speed
100 mph 44.7 m/s Fast car
1 mph 1.467 ft/s Imperial units
32.174 ft/s² 9.807 m/s² Standard gravity

Real-world uses

US driving Aviation Sports (baseball pitch)
Nautical Speed (Knots) The standard for maritime and aviation.

A knot is one nautical mile per hour. It is used worldwide for air and sea navigation because a nautical mile roughly corresponds to one minute of latitude.

Key formulas & rules

  • •1 knot = 1.852 km/h
  • •1 knot = 1.151 mph
  • •1 knot = 0.5144 m/s
  • •Nautical mile = 1852 meters
  • •Used by ships and planes
  • •Based on Earth's circumference

Examples

Input Output Note
10 knots 18.52 km/h Boat speed
1 knot 1.151 mph Standard
100 knots 185.2 km/h Light aircraft
500 knots 926 km/h Jet airliner

Real-world uses

Aviation Sailing Maritime navigation

Modes & formulas

1

Speed Conversion

• Enter a speed and choose the From and To units. • The calculator converts through m/s as the base unit. • Results are rounded to 4 decimal places.
value × factor_source / factor_target

1 m/s = 3.6 km/h = 2.23694 mph = 1.94384 knots = 3.28084 ft/s. These ratios are exact by definition of the units.

How to use it

Enter a value, choose the From and To units, and click Convert. The result appears instantly with a one-click copy button.

Frequently asked questions

What is a knot?
1 knot = 1 nautical mile per hour = 1.852 km/h. It's used in aviation and maritime navigation.
Why is m/s the base unit?
Because it's the SI unit of speed and makes the conversion factors clean. All other units are defined relative to it.
What is the difference between speed and velocity?
Speed is a scalar (how fast you are going). Velocity is a vector (how fast AND in what direction).
Why are knots used instead of mph?
Because a nautical mile corresponds to one minute of latitude on Earth, making navigation and chart reading much easier.
What is the SI unit of speed?
Meters per second (m/s).
How do I convert m/s to km/h?
Multiply by 3.6. For example, 5 m/s = 18 km/h.

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Read the full Speed Converter guide — examples & 18 FAQs