Speed Converter - mph to km/h, m/s, Knots

Convert mph to km/h, km/h to mph, knots to mph, m/s to km/h, and more. Speed conversion is essential for international travel, aviation, maritime navigation, and physics. Enter a value in the calculator below or browse the reference table.

Convert
= 1.61
mph × 1.609344 = km/h
Mile per Hour to Kilometer per Hour converter

Converting Speed Units

Speed measures how fast something moves over a given distance. The most common speed units are miles per hour (mph), kilometers per hour (km/h), meters per second (m/s), and knots. The US and UK use mph for road speeds, most other countries use km/h, and maritime and aviation industries use knots.

The key conversions are mph to km/h (multiply by 1.609), m/s to km/h (multiply by 3.6), and knots to mph (multiply by 1.151). Each converter shows the formula, worked examples, and a quick reference table.

Units Covered

speed Mile per Hour (mph) speed Kilometer per Hour (km/h) speed Meter per Second (m/s) speed Knot (kn) speed Foot per Second (ft/s)

Popular Converters

arrow_forwardmph to km/h1 mph = 1.61 km/h arrow_forwardkm/h to mph1 km/h = 0.6214 mph arrow_forwardm/s to km/h1 m/s = 3.6 km/h arrow_forwardkm/h to m/s1 km/h = 0.2778 m/s arrow_forwardmph to m/s1 mph = 0.447 m/s arrow_forwardm/s to mph1 m/s = 2.24 mph arrow_forwardkn to mph1 kn = 1.15 mph arrow_forwardkn to km/h1 kn = 1.85 km/h arrow_forwardmph to kn1 mph = 0.869 kn arrow_forwardft/s to mph1 ft/s = 0.6818 mph arrow_forwardmph to ft/s1 mph = 1.47 ft/s arrow_forwardm/s to ft/s1 m/s = 3.28 ft/s

Common Conversion Values

Value mph → km/h km/h → mph m/s → km/h kn → mph
1 1.61 0.6214 3.6 1.15
10 16.09 6.21 36 11.51
30 48.28 18.64 108 34.52
50 80.47 31.07 180 57.54
60 96.56 37.28 216 69.05
100 160.93 62.14 360 115.08
200 321.87 124.27 720 230.16

How These Conversions Work

Each unit pair has a fixed conversion factor defined by international standards. Multiply or divide by the factor to convert. Here are three examples:

1 mph = 1.61 km/h. Multiply by 1.609344. mph to km/h converter.

10 km/h = 6.21 mph. Multiply by 0.621371. km/h to mph converter.

1 m/s = 3.6 km/h. Multiply by 3.6. m/s to km/h converter.

Results above are rounded for readability. Each converter page shows the full-precision factor. For complete formulas with worked examples, visit the formulas hub.

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Frequently Asked Questions

Miles per hour (mph) is used in the US, UK, and a few other countries. Kilometers per hour (km/h) is used by most of the world. 1 mph = 1.609344 km/h. See the mph to km/h converter.
The most searched speed conversions are mph to km/h, km/h to mph, m/s to km/h, and knots to mph. These are essential for international travel, aviation, and physics.
A knot is one nautical mile per hour (approximately 1.151 mph or 1.852 km/h). Knots are used in aviation and maritime navigation because nautical miles relate directly to latitude and longitude. See the knots to mph converter.
Multiply meters per second by 3.6 to get km/h. This works because there are 3,600 seconds in an hour and 1,000 meters in a kilometer (3600/1000 = 3.6). See the m/s to km/h converter.
The speed of sound in dry air at 20 degrees Celsius is approximately 343 m/s, which equals about 767 mph or 1,235 km/h. This is known as Mach 1.
person Written by Sean Day verified Reviewed by UnitCompare update Last updated Mar 28, 2026