Speed Converter

Common Examples

Input	Result
60 mph	96.5606 km/h / 26.8224 m/s / 88.0 ft/s / 52.1381 kn
100 km/h	62.1371 mph / 27.7778 m/s / 91.1344 ft/s / 53.9957 kn
10 m/s	22.3694 mph / 36.0 km/h / 32.8084 ft/s / 19.4384 kn
30 knots	34.5234 mph / 55.56 km/h / 15.4333 m/s / 50.6232 ft/s
100 ft/s	68.1818 mph / 109.728 km/h / 30.48 m/s / 59.2484 kn

How It Works

All speed conversions use meters per second (m/s) as the intermediate base unit. The process is: convert the input value to m/s, then convert from m/s to each target unit.

Conversion factors to m/s:

1 mile per hour (mph) = 0.44704 m/s
1 kilometer per hour (km/h) = 0.277778 m/s
1 meter per second (m/s) = 1 m/s
1 foot per second (ft/s) = 0.3048 m/s
1 knot (kn) = 0.514444 m/s

Conversion factors from m/s:

m/s to mph: divide by 0.44704 (or multiply by 2.23694)
m/s to km/h: divide by 0.277778 (or multiply by 3.6)
m/s to ft/s: divide by 0.3048 (or multiply by 3.28084)
m/s to knots: divide by 0.514444 (or multiply by 1.94384)

These conversion factors come from the International System of Units (SI) and the definitions established by the International Bureau of Weights and Measures. One mph is derived from one mile (1,609.344 meters) per hour (3,600 seconds). One knot is defined as one nautical mile (1,852 meters) per hour.

Common Speed References

Walking speed: approximately 3.1 mph / 5 km/h / 1.4 m/s
Highway driving: approximately 65 mph / 104.6 km/h / 29.1 m/s
Speed of sound at sea level: approximately 767 mph / 1,235 km/h / 343 m/s

Worked Example

To convert 60 mph to km/h: First convert to m/s: 60 x 0.44704 = 26.8224 m/s. Then convert from m/s to km/h: 26.8224 / 0.277778 = 96.5606 km/h. To ft/s: 26.8224 / 0.3048 = 88.0 ft/s. To knots: 26.8224 / 0.514444 = 52.1381 kn. This confirms that 60 mph is roughly 97 km/h, a useful reference for travel between countries using different speed systems.

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Frequently Asked Questions

How do you convert mph to km/h?

Multiply the mph value by 1.60934 to get km/h. For example, 60 mph x 1.60934 = 96.56 km/h. Alternatively, multiply by 0.44704 to get m/s first, then multiply by 3.6 to get km/h.

What is a knot and where is it used?

A knot is a unit of speed equal to one nautical mile per hour (1.852 km/h or 1.15078 mph). Knots are primarily used in aviation and maritime navigation. The term comes from the historical practice of measuring a ship's speed by counting knots on a rope paid out over a fixed time.

What is the difference between speed and velocity?

In everyday language, speed and velocity are used interchangeably. In physics, speed is a scalar (magnitude only), while velocity is a vector (magnitude and direction). For unit conversion purposes, the distinction does not affect the calculation.

Why do some countries use mph and others use km/h?

The United States, the United Kingdom, and a few other countries use miles per hour for road speed limits and vehicle speedometers. Most of the world uses kilometers per hour as part of the metric system. The UK uses mph on roads but km/h in some scientific and aviation contexts.

How accurate are these conversions?

The conversion factors used here are precise to at least 6 significant digits, matching internationally defined values. For everyday purposes such as driving, travel planning, or weather reports, this precision is more than sufficient.