Convert speed units — km/h, mph, m/s, knots, Mach.
| Unit | Name | Value |
|---|---|---|
| m/s | Meter per Second | 0.44704 |
| km/h | Kilometer per Hour | 1.6093427 |
| ft/s | Foot per Second | 1.4666667 |
| kn | Knot | 0.86897699 |
| Mach | Mach | 0.001313703 |
Common mile per hour values converted to knot — factor: 1 mph = 0.869 kn
| Mile per Hour (mph) | Knot (kn) | Context |
|---|---|---|
| 3 mph | 2.607 kn | Slow walk |
| 6 mph | 5.214 kn | Fast walk |
| 10 mph | 8.69 kn | Slow cycle |
| 20 mph | 17.38 kn | Fast cycle |
| 30 mph | 26.07 kn | City road |
| 40 mph | 34.76 kn | Rural road |
| 50 mph | 43.45 kn | Rural road |
| 60 mph | 52.14 kn | Motorway |
| 70 mph | 60.83 kn | Fast motorway |
| 80 mph | 69.52 kn | Fast motorway |
| 100 mph | 86.9 kn | Sports car |
| 120 mph | 104.3 kn | Sports car |
| 200 mph | 173.8 kn | High-speed train |
| 550 mph | 477.9 kn | Jet airliner |
| 767 mph | 666.5 kn | Speed of sound |
Converting mile per hour to knot is essential for drivers, pilots, engineers, and scientists working across different measurement systems. Road speed limits, aviation airspeed, nautical navigation, and physics calculations each use different speed units, making quick and accurate conversion a practical everyday skill.
Key reference points: 5 mph = 4.345 kn and 10 mph = 8.69 kn. At higher speeds, 100 mph = 86.9 kn. For reverse conversion, multiply kn values by 1.151 to get back to mph.
All conversions use the internationally recognized factor of exactly 1 mph = 0.869 kn. Calculations are performed in IEEE 754 double-precision floating point, giving accuracy to at least 8 significant figures — more than sufficient for any practical application.
Formula: Knot = Mile per Hour × 0.86897699
Multiply any mile per hour value by 0.86897699 to get knot. One mile per hour equals 0.86897699 kn.
Reverse: Mile per Hour = Knot × 1.1507785
mph × 0.8690 = knots. Round to × 0.87.
One mph is slightly less than one knot.
knots × 1.1508 = mph.
Reads road speed limits and vehicle speedometers in miles per hour.
Observes UK speed limits (20/30/60/70 mph) on British roads.
Monitors lap speeds and vehicle performance in mph at US oval tracks.
Reports hurricane and tornado wind speeds in mph for US audiences.
References historical aircraft speeds in mph from US/UK aviation records.
Measures and enforces speed limits in mph in the US and UK.
Miles per hour traces its roots to Imperial Britain, where the mile was standardized as 1,760 yards in the 18th century. The UK adopted mph for road use and exported it to its colonies, explaining why the US, UK, and a handful of other nations still use it.
The United States, United Kingdom, Liberia, and Myanmar are the primary countries still using mph for road speeds. US Interstate speed limits are typically 65-75 mph, while UK motorways are limited to 70 mph.
Interesting fact: The world's fastest production car, the Bugatti Chiron Super Sport, reaches 304 mph (490 km/h). The US air speed record stands at 2,193 mph set by the SR-71 Blackbird.
The knot is a unit of speed equal to one nautical mile per hour, approximately 1.852 km/h or 0.514 m/s. Its name comes from the historical practice of measuring ship speed by counting knots on a rope thrown overboard.
Knots are the international standard for maritime and aviation speed. All commercial aircraft, warships, and weather forecasts use knots. Air traffic control worldwide communicates in knots and feet.
Interesting fact: The cruising speed of a Boeing 747 is about 490 knots (907 km/h). Ocean currents are typically 0.5-1 knot, while Category 5 hurricanes sustain winds above 137 knots.