Speed Converter
Last updated: 2026-06-25
Speed conversion uses factors such as 1 m/s = 3.6 km/h, 1 mph = 1.60934 km/h, 1 knot = 1.852 km/h and Mach 1 ≈ 1,225 km/h (standard sea-level speed of sound 340.29 m/s), by collecting every value into m/s first and then converting to the unit you want.
Enter a value below and pick a unit; m/s, km/h, mph, knots and Mach update instantly.
Enter a speed
Results (all units)
| Unit | Value |
|---|
How to use
- Enter a value — Type the speed value you want to convert.
- Pick the source unit — Choose the unit of your value (for example km/h or Mach) from the dropdown.
- Read the results — m/s, km/h, mph, knots and Mach all update instantly in the table.
Mach conversion and speed factors
Speed conversion works by converting every unit to meters per second and then dividing back into the unit you want. km/h, mph and knots are all distance-per-hour units that convert by fixed factors, while Mach is a ratio to the speed of sound and is converted against the standard speed of sound.
| Unit | In m/s | Note |
|---|---|---|
| m/s (meters/second) | 1 m/s | base unit |
| km/h (kilometers/hour) | 0.277778 m/s | 1 m/s = 3.6 km/h |
| mph (miles/hour) | 0.44704 m/s | 1 mph ≈ 1.60934 km/h |
| Knot | 0.514444 m/s | 1 knot = 1.852 km/h |
| Mach | 340.29 m/s | standard sea-level speed of sound |
For example, a highway speed of 100 km/h is about 27.78 m/s and about 62.14 mph. A cruising airliner at Mach 0.85 travels about 1,041 km/h (at the standard speed of sound). For more conversion tips, see the unit conversion cheat sheet.
Frequently asked questions (FAQ)
How many km/h is 1 knot?
One knot is exactly 1.852 km/h. A knot is one nautical mile (1,852 m) per hour and is used for ships and aircraft. For example, 10 knots is 18.52 km/h.
How fast is Mach 1 in km/h?
Mach is the ratio to the speed of sound. In standard sea-level atmosphere (15 °C) the speed of sound is about 340.29 m/s, or roughly 1,225 km/h, so Mach 1 is about 1,225 km/h. Because the speed of sound changes with altitude and temperature, this is an approximation for standard conditions.
What is 60 mph in km/h?
One mph is about 1.60934 km/h, so 60 mph is about 96.56 km/h. US road signs use mph, so multiply by roughly 1.6 to read them in km/h.
How do I convert m/s to km/h?
One m/s is 3.6 km/h. Multiply m/s by 3.6 to get km/h. For example, 10 m/s is 36 km/h; to go the other way, divide km/h by 3.6.
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Last updated: 2026-06-25