Common Speed Conversions
The table below shows the most frequently looked-up km/h to mph conversions, covering typical road speeds from city limits to motorway cruising. Use the speed converter above for any other value instantly, or check the exact formulas below.
| km/h | mph | Notes |
|---|---|---|
| 30 km/h | 18.6 mph | Residential / school zones |
| 50 km/h | 31.1 mph | Typical city speed limit |
| 60 km/h | 37.3 mph | Urban arterial roads |
| 80 km/h | 49.7 mph | Rural roads |
| 100 km/h | 62.1 mph | Motorway (many countries) |
| 110 km/h | 68.4 mph | Motorway (AU, NZ, others) |
| 120 km/h | 74.6 mph | European motorway limit |
| 130 km/h | 80.8 mph | French / Spanish motorways |
How to Convert km/h to mph
To convert kilometres per hour to miles per hour, multiply the km/h value by 0.621371. This is the exact conversion factor because one mile equals 1.609344 kilometres exactly.
Example: 100 km/h x 0.621371 = 62.14 mph.
A quick mental shortcut: divide by 8 and multiply by 5. This gives you a rough answer that is accurate to about 1%. For 80 km/h: 80 / 8 x 5 = 50 mph. The exact answer is 49.7 mph, so the shortcut works well for everyday estimates.
How to Convert Knots to km/h
One knot is defined as one nautical mile per hour. A nautical mile is exactly 1,852 metres, so the conversion is precise: 1 knot = 1.852 km/h.
To convert knots to km/h, multiply by 1.852. To convert knots to mph, multiply by 1.15078. Knots are the standard unit of speed in aviation and maritime navigation worldwide, so this conversion is useful when reading weather reports, flight data, or vessel information.
Example: 30 knots x 1.852 = 55.56 km/h = 34.52 mph.
How to Convert m/s to km/h
To convert metres per second to kilometres per hour, multiply by 3.6. This factor comes from the fact that there are 3,600 seconds in an hour and 1,000 metres in a kilometre: 3600 / 1000 = 3.6.
Example: 10 m/s x 3.6 = 36 km/h. And 30 m/s x 3.6 = 108 km/h (about 67.1 mph).
Metres per second is the SI unit for speed and is commonly used in physics, meteorology, and scientific contexts. When wind speed or athlete performance is given in m/s, multiplying by 3.6 gives the familiar km/h equivalent.