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ToolPika

Speed Converter

Type a speed and pick the units. Handy for speed limits abroad, running pace, wind and boating.

62.137119 mph

100 km/h = 62.137119 mph · 1 km/h = 0.62137119 mph

In all units: 100 km/h
Kilometers per hour100 km/h
Miles per hour62.137119 mph
Meters per second27.777778 m/s
Knots53.99568 kn
Feet per second91.134442 ft/s

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How it works

Every unit is stored as its value in meters per second:

Unit In m/s Why
Kilometers per hour 1 ÷ 3.6 ≈ 0.27778 1,000 m ÷ 3,600 s
Miles per hour 0.44704 1,609.344 m ÷ 3,600 s
Knots 0.51444 1,852 m ÷ 3,600 s
Feet per second 0.3048 1 ft = 0.3048 m

All of these are exact, because the mile, the nautical mile and the foot are defined in meters.

Examples

  • Driving abroad. 100 km/h is 62.14 mph, and 70 mph is 112.65 km/h.
  • Town speed limits. 30 mph is 13.41 m/s, or 48.28 km/h.
  • Sailing and wind. 20 knots is 37.04 km/h.
  • Sprinting. Running 100 m in 9.58 seconds averages 10.44 m/s, which is 37.58 km/h.
  • Physics. 60 mph is exactly 88 feet per second.

Quick mental conversions

  • km/h → mph: multiply by 0.6, then add a little (100 km/h → 60, real answer 62).
  • mph → km/h: multiply by 1.6 (50 mph → 80 km/h, real answer 80.47).
  • m/s → km/h: multiply by 3.6 exactly.

Frequently asked questions

How do I convert km/h to mph?

Divide by 1.609344 (the number of kilometers in a mile), or multiply by about 0.6214. 100 km/h is 62.14 mph.

How do I convert mph to km/h?

Multiply by 1.609344. A 70 mph motorway limit is 112.65 km/h.

What is a knot?

One nautical mile per hour, which is exactly 1.852 km/h or about 1.151 mph. Knots are used at sea, in aviation and for wind speed.

How do I convert m/s to km/h?

Multiply by 3.6, because an hour has 3,600 seconds and a kilometer 1,000 meters. 10 m/s is 36 km/h.

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