Speed Converter

Convert km/h, mph, m/s, knots, Mach and more.

100 km/h=62.137119 mph
1 km/h = 0.62137119 mph 1 mph = 1.609344 km/h

All conversions

27.777778
Meters per second m/s
100
Kilometers per hour km/h
62.137119
Miles per hour mph
53.99568
Knot kn
91.134442
Feet per second ft/s
2,777.7778
Centimeters per second cm/s
0.081628762
Mach (sea level, 15 °C) Ma
9.2656693e-8
Speed of light c

Common speed conversions

km/h to mph
km/hmph
10.62137119
53.106856
106.2137119
2515.53428
5031.06856
10062.137119
1000621.37119
mph to km/h
mphkm/h
11.609344
58.04672
1016.09344
2540.2336
5080.4672
100160.9344
10001,609.344
m/s to km/h
m/skm/h
13.6
518
1036
2590
50180
100360
10003,600
kn to km/h
knkm/h
11.852
59.26
1018.52
2546.3
5092.6
100185.2
10001,852

Unit reference

UnitSymbolEquals
Meters per secondm/sbase unit
Kilometers per hourkm/h1 km/h = 0.2777777778 m/s
Miles per hourmph1 mph = 0.44704 m/s
Knotkn1 kn = 0.5144444444 m/s
Feet per secondft/s1 ft/s = 0.3048 m/s
Centimeters per secondcm/s1 cm/s = 0.01 m/s
Mach (sea level, 15 °C)Ma1 Ma = 340.294 m/s
Speed of lightc1 c = 299,792,458 m/s

About this speed converter

Convert speeds between metric, imperial and nautical units. Use it for speed limits, running pace, wind speeds, aircraft and ships. Enter a value once and see km/h, mph, m/s, knots, ft/s and Mach together.

Planning a trip? Combine it with the length converter and time converter to estimate distances and durations.

Driving abroad

Translate speed limits between km/h and mph, such as 100 km/h ≈ 62 mph and 70 mph ≈ 113 km/h.

Sailing & aviation

Knots are one nautical mile per hour; convert to km/h or mph for passage planning.

Sports & weather

Compare sprint speeds in m/s, cycling in km/h and wind forecasts in mph or knots.

Tips for accurate results

Quick mental math

To turn mph into km/h, multiply by about 1.6. To turn km/h into mph, multiply by about 0.62.

About Mach

Mach 1 depends on temperature and altitude. This tool uses the speed of sound at sea level and 15 °C (about 340.3 m/s).

Frequently asked questions

How do I convert km/h to mph?

Divide the speed in km/h by 1.609344, or multiply by 0.621371. For example, 100 km/h is about 62.14 mph.

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

Multiply meters per second by 3.6. For example, 10 m/s equals 36 km/h.

What is a knot?

A knot is one nautical mile (1,852 m) per hour, roughly 1.852 km/h or 1.15078 mph.

How fast is the speed of light?

Light travels at exactly 299,792,458 m/s in a vacuum, about 1.079 billion km/h.

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