Speed Converter
Convert between different speed units instantly and accurately
Quick Conversions
Speed Conversion Reference Table
This comprehensive table shows conversion factors between commonly used speed units. To convert from any unit in the left column to meters per second, multiply by the conversion factor shown.
| Unit | Symbol | Equals (in m/s) | Common Use |
|---|---|---|---|
| Meters per second | m/s | 1 | Scientific calculations |
| Kilometers per hour | km/h | 0.277778 | Road traffic (metric) |
| Miles per hour | mph | 0.44704 | Road traffic (imperial) |
| Feet per second | ft/s | 0.3048 | Engineering applications |
| Knots | kn | 0.514444 | Maritime and aviation |
| Mach (sea level) | M | 343.6 | Aviation (supersonic) |
| Kilometers per second | km/s | 1000 | Astronomy, space travel |
| Miles per second | mi/s | 1609.344 | Astronomy calculations |
| Speed of light | c | 299,792,458 | Physics and astronomy |
How to Convert Speed Units
Speed conversion involves multiplying the original value by a specific conversion factor. The formula for converting speed units is:
Step-by-Step Conversion Process
Step 1: Identify the conversion factor (1 km/h = 0.621371 mph)
Step 2: Multiply 100 × 0.621371 = 62.1371 mph
Result: 100 km/h = 62.14 mph
Step 1: Identify the conversion factor (1 mph = 0.44704 m/s)
Step 2: Multiply 60 × 0.44704 = 26.8224 m/s
Result: 60 mph = 26.82 m/s
Step 1: Identify the conversion factor (1 m/s = 3.6 km/h)
Step 2: Multiply 10 × 3.6 = 36 km/h
Result: 10 m/s = 36 km/h
Popular Speed Conversions
These are the most frequently searched speed conversions with their exact values for quick reference.
Metric to Imperial
- 50 km/h = 31.07 mph
- 80 km/h = 49.71 mph
- 100 km/h = 62.14 mph
- 120 km/h = 74.56 mph
- 160 km/h = 99.42 mph
- 200 km/h = 124.27 mph
Imperial to Metric
- 30 mph = 48.28 km/h
- 55 mph = 88.51 km/h
- 65 mph = 104.61 km/h
- 70 mph = 112.65 km/h
- 100 mph = 160.93 km/h
- 150 mph = 241.40 km/h
Meters per Second Conversions
- 5 m/s = 18 km/h = 11.18 mph
- 10 m/s = 36 km/h = 22.37 mph
- 15 m/s = 54 km/h = 33.55 mph
- 20 m/s = 72 km/h = 44.74 mph
- 25 m/s = 90 km/h = 55.92 mph
- 30 m/s = 108 km/h = 67.11 mph
Maritime & Aviation
- 10 knots = 18.52 km/h = 11.51 mph
- 20 knots = 37.04 km/h = 23.02 mph
- 50 knots = 92.60 km/h = 57.54 mph
- Mach 1 = 1,235 km/h = 767 mph
- Mach 2 = 2,470 km/h = 1,534 mph
- Mach 3 = 3,704 km/h = 2,301 mph
Real-World Speed Examples
Here are common speeds from everyday life and nature to help put speed conversions into perspective.
| Object/Activity | m/s | km/h | mph |
|---|---|---|---|
| Average walking pace | 1.4 | 5 | 3.1 |
| Jogging pace | 3 | 11 | 6.7 |
| Cycling (leisure) | 5.5 | 20 | 12.4 |
| City car speed limit | 13.9 | 50 | 31 |
| Highway speed limit | 30 | 110 | 68 |
| Usain Bolt (peak sprint) | 12.4 | 44.7 | 27.8 |
| Cheetah (top speed) | 33 | 120 | 75 |
| Peregrine falcon (dive) | 90 | 322 | 200 |
| High-speed train | 97 | 350 | 217 |
| Commercial jet cruise | 250 | 900 | 559 |
| Sound (at sea level) | 343 | 1,235 | 767 |
| Earth’s orbital speed | 29,783 | 107,218 | 66,623 |
Speed vs Velocity: What’s the Difference?
While often used interchangeably, speed and velocity have distinct meanings in physics.
Speed
Speed is a scalar quantity that refers to how fast an object is moving. It only has magnitude and no direction.
If you drive 60 km/h, your speed is 60 km/h regardless of whether you’re going north, south, east, or west.
Velocity
Velocity is a vector quantity that includes both magnitude and direction. It tells you how fast something moves and in which direction.
If you drive 60 km/h north, your velocity is 60 km/h north. The direction is essential for velocity.
Common Speed Unit Systems
Metric System (SI Units)
The International System of Units uses meters per second (m/s) as the standard unit for speed. This system is used worldwide for scientific calculations and in most countries for everyday measurements.
- Primary unit: Meters per second (m/s)
- Common unit: Kilometers per hour (km/h)
- Used in: Europe, Asia, Australia, Africa, South America
Imperial System
The imperial system primarily uses miles per hour (mph) for everyday speed measurements and feet per second (ft/s) for technical applications.
- Primary unit: Miles per hour (mph)
- Technical unit: Feet per second (ft/s)
- Used in: United States, some Caribbean nations
Maritime and Aviation
Knots are the standard speed unit in maritime and aviation contexts worldwide, regardless of whether the country uses metric or imperial systems.
- 1 knot = 1 nautical mile per hour
- 1 nautical mile = 1.852 kilometers
- Used for: Ships, boats, aircraft navigation
Frequently Asked Questions
How do you convert km/h to mph?
To convert kilometers per hour to miles per hour, multiply the speed value by 0.621371. For example, 100 km/h × 0.621371 = 62.14 mph. Alternatively, you can use our converter above for instant results.
What is the difference between knots and mph?
Knots measure nautical miles per hour, while mph measures statute miles per hour. One knot equals approximately 1.151 mph. Knots are primarily used in maritime and aviation, while mph is used for road travel in countries using the imperial system.
How many meters per second is 100 km/h?
100 km/h equals 27.78 m/s. To convert km/h to m/s, divide the speed by 3.6. This conversion is useful when working with scientific calculations that require SI units.
Why are different speed units used in different countries?
Different speed units reflect historical measurement systems. Most countries adopted the metric system and use km/h, while the United States and a few other nations continue using the imperial system with mph. Maritime and aviation industries universally use knots for consistency in international operations.
What is Mach speed?
Mach speed is the ratio of an object’s speed to the speed of sound in the surrounding medium. Mach 1 equals the speed of sound (approximately 343 m/s or 1,235 km/h at sea level). Mach 2 is twice the speed of sound, and so on. The actual speed varies with altitude and temperature.
How fast is the speed of light?
The speed of light in vacuum is exactly 299,792,458 meters per second, approximately 1,079,252,848 km/h or 670,616,629 mph. This is the fastest speed possible in the universe according to Einstein’s theory of relativity.
Can I convert between speed and distance?
Speed and distance are different types of measurements. However, they are related through time using the formula: Speed = Distance ÷ Time. You cannot directly convert speed to distance without knowing the time duration.
What speed unit should I use for running pace?
Runners typically express pace in minutes per kilometer (min/km) or minutes per mile (min/mi), which is the inverse of speed. However, speed can be expressed in km/h or mph. A 5-minute kilometer pace equals 12 km/h or 7.5 mph.
How accurate are speed conversions?
Speed conversions using standard conversion factors are mathematically precise. Our converter provides results accurate to multiple decimal places. For most practical purposes, rounding to 2 decimal places is sufficient.
Why do speedometers show both km/h and mph?
Many vehicles sold internationally feature dual-unit speedometers to accommodate drivers in different countries. This allows the same vehicle model to be used in countries using either the metric system (km/h) or imperial system (mph) without modification.