Speed Converter
Convert between mph, km/h, m/s, ft/s, knots, and Mach. Real-time results with travel calculator.
| Unit | Value |
|---|---|
| Miles per hour (mph) | — |
| Kilometers per hour (km/h) | — |
| Meters per second (m/s) | — |
| Feet per second (ft/s) | — |
| Knots (nmi/h) | — |
| Mach (at sea level) | — |
| Description | mph | km/h | m/s |
|---|---|---|---|
| Average walking pace | 3 | 4.8 | 1.3 |
| Jogging / easy run | 6 | 9.7 | 2.7 |
| Competitive sprint (100m world record) | 27.8 | 44.7 | 12.4 |
| City speed limit (typical) | 25–35 | 40–56 | 11–16 |
| Highway / motorway speed | 60–75 | 97–121 | 27–34 |
| High-speed train (TGV, Shinkansen) | 200 | 322 | 89 |
| Speed of sound (sea level, 20°C) | 767 | 1235 | 343 |
| Mach 2 (fighter jet) | 1535 | 2470 | 686 |
| Low Earth orbit | 17,500 | 28,160 | 7,822 |
| Speed of light | 670,616,629 | 1,079,252,848 | 299,792,458 |
How to use
- Enter a speed value in either field and select the units — the result updates instantly
- Use the ⇄ button to swap the from and to units
- The "All Units at a Glance" table shows your entered speed in every unit simultaneously
- Distance → Time: Enter a distance and speed to calculate travel time
- Time → Distance: Enter a duration and speed to calculate distance covered
- Mach speed uses 343 m/s (speed of sound at sea level, approximately 20°C)
About this Speed Converter
Speed units vary by country and context — mph in the US and UK road signage, km/h almost everywhere else, knots at sea and in aviation, and meters per second in scientific work — making conversion a common need for travel, sports, and technical reference.
Key conversion factors
- 1 mph = 1.60934 km/h
- 1 km/h = 0.62137 mph
- 1 knot (nautical mile per hour) = 1.852 km/h = 1.15078 mph
- 1 m/s = 3.6 km/h = 2.23694 mph
Why aviation and marine use knots
A knot is defined as one nautical mile per hour, and a nautical mile is based on one minute of latitude — a unit directly tied to navigation and the Earth's geometry, which is why ships and aircraft have used knots for centuries rather than switching to mph or km/h like road vehicles.
Worked example
A car traveling at 65 mph is going 65 × 1.60934 = 104.6 km/h. A wind speed reported as 20 knots converts to 20 × 1.852 = 37.04 km/h, or roughly 23 mph.