Speed Converter
Convert between km/h, mph, m/s, knots, and more speed units.
Each step along the axis is ten times the one before — the speed units span 3 orders of magnitude, so a straight scale would bunch almost all of them at one end.
Instant insight
That is about 71.43% of walking pace
1 metres per second — About 5 km/h.
Anchors like this are the quickest way to catch an answer that is out by a factor of ten.
Knots and mph are not interchangeable
A knot is one nautical mile per hour — 1.852 km/h, about 15% more than a statute mph.
Aviation and marine figures are in knots; road figures are not. Mixing them understates speed by a noticeable margin.
Check the direction of the conversion
Going from mps to kph, the number should get bigger if the new unit is smaller, and smaller if it is bigger.
If it moved the wrong way, the factor has been applied upside down — the most common conversion error there is.
Worked out in your browser — nothing is sent anywhere. Comparison figures are approximate.
Common conversions
Quick Reference — 1 unit = ? Kilometers per Hour (km/h)
| Unit | Value |
|---|---|
| Meters per Second (m/s) | 3.59999712 |
| Kilometers per Hour (km/h) | 1 |
| Miles per Hour (mph) | 1.609342713 |
| Feet per Second (ft/s) | 1.097279122 |
| Knot (kn) | 1.851996918 |
| Mach (at sea level) | 1225.04302 |
Formula
Multiply by (from factor / to factor)
Everyday Uses
Driving abroad
The sign says 100 km/h and your speedometer thinks in mph (it's 62) — convert limits before the rental car leaves the lot.
Running pace
Treadmill in km/h, race pace in min/mile — convert speeds so your training targets translate to race day.
Wind and weather
Forecast says 40 knots — how bad is that? (74 km/h — very windy.) Convert wind speeds for sailing, flying, or storm prep.
Physics problems
Convert between m/s, km/h, and mph so homework answers land in the units the question demands.
Boat and wind speed
Convert between knots, mph and km/h — marine and aviation use knots where road signs do not.
Machine and belt speeds
Convert feet per minute to metres per second when reading equipment specifications.
Frequently Asked Questions
How do you convert between km/h and mph?
1 mph = 1.60934 km/h. 1 km/h = 0.62137 mph. To convert mph to km/h, multiply by 1.609 (or ×8÷5). To convert km/h to mph, multiply by 0.621 (or ×5÷8). Common conversions: 30 mph = 48.3 km/h (urban speed limit in UK). 60 mph = 96.6 km/h. 70 mph = 112.7 km/h (UK motorway limit). 100 km/h = 62.1 mph. 120 km/h = 74.6 mph (European motorway). 130 km/h = 80.8 mph.
How fast is the speed of sound (Mach 1), and what is Mach number?
Mach 1 ≈ 340.29 m/s = 1,225 km/h = 761.2 mph at sea level (20°C, dry air). Speed of sound varies with temperature and medium: at 0°C it is 331 m/s; at 35,000 ft altitude (cruising jets), about 295 m/s = 1,062 km/h. Mach number = object speed ÷ local speed of sound. Subsonic: Mach <0.8; Transonic: 0.8–1.2; Supersonic: 1.2–5; Hypersonic: >5. Concorde cruised at Mach 2 (~2,180 km/h); SR-71 Blackbird: Mach 3.3 (~3,540 km/h).
What is a knot and why is it used in aviation and maritime?
1 knot = 1 nautical mile per hour = 1.852 km/h = 1.151 mph. Nautical miles and knots are used in aviation and maritime because 1 nautical mile = 1 arcminute of latitude, making navigation calculations on spherical charts much simpler — distances in nautical miles correspond directly to degrees and minutes on a map. Commercial aircraft cruise at 450–490 knots (830–910 km/h); a typical sailing boat makes 5–10 knots; ocean liners cruise at 20–25 knots.
How do you convert m/s to km/h and mph?
To convert m/s to km/h: multiply by 3.6 (since 1 m/s × 3600 s/hr ÷ 1000 m/km = 3.6). To convert km/h to m/s: divide by 3.6. To convert m/s to mph: multiply by 2.237. Examples: 10 m/s = 36 km/h = 22.4 mph (fast sprint speed); 30 m/s = 108 km/h = 67 mph; 100 m/s = 360 km/h = 224 mph. Wind speeds in weather reports are often given in m/s (meteorology) or mph/km/h (general public). Beaufort scale: 7 m/s = near gale; 17 m/s = storm.
How fast do different things travel in everyday comparison?
Speed reference benchmarks: Walking: 1.4 m/s = 5 km/h = 3.1 mph. Cycling: 5–10 m/s = 18–36 km/h. Sprinting (elite): 12.4 m/s = 44.7 km/h (Usain Bolt record). Car (motorway): 28–36 m/s = 100–130 km/h. Commercial aircraft: 245 m/s = 880 km/h. Speed of sound: 340 m/s = 1,225 km/h. Bullet (rifle): 900–1,200 m/s. Space Shuttle orbital speed: 7,800 m/s = 28,080 km/h. Speed of light: 299,792,458 m/s = 1.08 billion km/h.