Metric and imperial speed conversions
Speed Converter
Convert metres per second, kilometres per hour, miles per hour and knots instantly with our free online speed converter. No signup required, works offline.
Convert Speed
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How to Convert Speed Units
Speed conversions are part of everyday driving, running, aviation and weather reporting. Speed limits are in miles per hour in the US and UK, kilometres per hour across Europe and most of the world, and knots in aviation and maritime contexts. This converter handles all four common units so you can compare speeds across countries and disciplines instantly.
Key Speed Conversion Formulas
1 km/h = 0.621371 mph
1 mph = 1.60934 km/h
1 knot = 1.852 km/h (one nautical mile per hour)
1 m/s = 3.6 km/h
Every unit in this converter is expressed relative to metres per second (the SI unit of speed), then converted to your target unit. This guarantees consistent results: whether you convert mph to knots or km/h to m/s, the maths uses exact factors with no rounding drift.
Common Speed Conversions
| Speed | Equals | Real-world reference |
|---|---|---|
| 60 mph | 96.6 km/h | Typical UK motorway speed limit |
| 100 km/h | 62.1 mph | Common European motorway limit |
| 70 mph | 112.7 km/h | UK dual carriageway limit |
| 10 knots | 18.5 km/h | A brisk sailing boat speed |
| 1 m/s | 3.6 km/h | A gentle walking pace |
| 120 km/h | 74.6 mph | French motorway limit |
When Do You Need a Speed Converter?
- Driving abroad: Speed limits are signed in km/h across Europe; hire cars often display both
- Fitness: Treadmills and running apps mix mph, km/h and min/km pace units
- Aviation and sailing: Wind and aircraft speeds are quoted in knots, while ground speeds may be in mph or km/h
- Weather: Storm warnings report wind speed in mph in the UK, knots at sea, and km/h or m/s elsewhere
- Vehicle specs: Comparing top speeds and acceleration figures quoted in different units by different manufacturers
Why Knots Are Still Used
Knots (nautical miles per hour) have survived in aviation and shipping because navigation is based on latitude and longitude. One nautical mile equals one minute of latitude, which makes nautical-mile-based speed directly useful for plotting positions on a chart. One knot is 1.852 km/h exactly, and while it looks like an odd number in metric terms, it is the natural unit for anyone working with maps and sextants. For everyone else, this converter makes knot values readable in the units you actually use.
Frequently Asked Questions
How do I convert mph to km/h?
Multiply the speed in mph by 1.60934 to get km/h. For example, 60 mph × 1.60934 = 96.6 km/h. To go the other way, divide km/h by 1.60934. Our speed converter does this instantly.
What is a knot in mph?
One knot equals 1.15078 mph. A typical cruising aircraft speed of 450 knots is about 518 mph. To convert knots to mph, multiply by 1.151.
How fast is 100 km/h in mph?
100 km/h is 62.14 mph. This is a common motorway speed limit across Europe and Australia.
What is the difference between speed and pace?
Speed is distance per unit of time (km/h, mph). Pace is time per unit of distance (minutes per kilometre or mile), used by runners. A 5 min/km pace equals 12 km/h.
Why does the UK use mph while Europe uses km/h?
The UK retained imperial road signage when it adopted metric units for most other measurements. All UK speed limits are in miles per hour, so drivers crossing the Channel need fast, accurate conversion.
Does the speed converter work offline?
Yes. Conversions are calculated locally in your browser with exact factors, so the tool works offline and no data leaves your device.