Unit Converters
Speed Unit Converter
Convert between mph, km/h, m/s, ft/s, knots, and Mach number instantly. Free, browser-based speed converter - no install required.
Speed in context
100.00 km/h
What is X mph in km/h?
To convert miles per hour to kilometers per hour, multiply by 1.60934. To go the other way, multiply km/h by 0.621371. Common road speed conversions:
Common speed conversions
| Value | Result |
|---|---|
| 30 mph | 48.28 km/h |
| 45 mph | 72.42 km/h |
| 60 mph | 96.56 km/h |
| 70 mph | 112.65 km/h |
| 80 mph | 128.75 km/h |
| 100 mph | 160.93 km/h |
| 50 km/h | 31.07 mph |
| 80 km/h | 49.71 mph |
| 100 km/h | 62.14 mph |
| 120 km/h | 74.56 mph |
| 130 km/h | 80.78 mph |
| 1 knot | 1.852 km/h |
| 1 knot | 1.15078 mph |
| Mach 1 | 340.29 m/s |
| Mach 1 | 1225.04 km/h |
| Mach 1 | 761.21 mph |
How speed conversion works
All conversions go through meters per second (m/s) as the base unit. The input is multiplied by the source unit's m/s factor, then divided by the target unit's factor. Conversion factors use exact international definitions where available (mph via the exact yard, km/h via exact kilometer, knots via exact nautical mile). Mach number uses the standard sea-level value of 340.29 m/s. The actual speed of sound varies with altitude and temperature.
Speed context anchors
| Speed | km/h | mph |
|---|---|---|
| Walking pace | ~5 km/h | ~3.1 mph |
| Cycling | ~25 km/h | ~15.5 mph |
| Car (highway) | ~120 km/h | ~74.6 mph |
| Commercial aircraft | ~900 km/h | ~560 mph |
| Speed of sound (sea level) | 1,235 km/h | 767 mph |
| SR-71 Blackbird (fastest jet) | ~3,530 km/h (Mach 3.3) | ~2,193 mph |
| Earth’s orbital speed | ~107,000 km/h | ~66,500 mph |
| Speed of light | ~1,079,252,848 km/h | ~670,616,629 mph |
Speed limits by country
| Country | Urban | Rural | Highway (motorway) |
|---|---|---|---|
| United States | 25–35 mph (40–56 km/h) | 55–65 mph | 65–85 mph (105–137 km/h) |
| United Kingdom | 30 mph (48 km/h) | 60 mph | 70 mph (113 km/h) |
| Germany | 50 km/h (31 mph) | 100 km/h | No general limit (Autobahn); advisory 130 km/h |
| France | 50 km/h | 80 km/h | 130 km/h (81 mph) |
| Australia | 50 km/h | 100 km/h | 110 km/h (68 mph) |
| Canada | 50 km/h | 80–90 km/h | 100–110 km/h |
| Japan | 40 km/h | 60 km/h | 100–120 km/h |
Terminal velocity reference
Terminal velocity is the maximum speed a falling object reaches when drag force equals gravitational force. For a human in freefall:
- Stable belly-to-earth position: approximately 195 km/h (120 mph). This is the standard position for recreational skydiving.
- Head-down (freefly) position: approximately 240–290 km/h (150–180 mph). Competitive speed skydivers reach up to 400 km/h+ by adopting a head-down feet-up position.
- Speed skydiving record: over 500 km/h (310 mph) in special suits on a specific body position, achieved in competitions.