Speed unit converter
Convert speed units — m/s, km/h, km/s, m/min, mph, ft/s, knots, Mach and the speed of light — with Mach at the sea-level standard 340.29 m/s.
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Result
The source to target line first, then every common unit.
Enter a speed to convert
Units: 0
What this tool does
- Convert mph to km/h and m/s for reviews, videos and datasheets.
- Translate knots into metric speeds — 1 knot = 1.852 km/h.
- Check conventions before coding: Mach is 340.29 m/s at sea level and the speed of light is exactly 299792458 m/s.
Example
Input
1
Output
千米每小时 (km/h) → 米每秒 (m/s)：1 km/h = 0.277778 m/s 米每秒 (m/s) = 0.277778 m/s 千米每小时 (km/h) = 1 km/h 千米每秒 (km/s) = 0.000278 km/s 米每分 (m/min) = 16.666667 m/min 英里每小时 (mph) = 0.621371 mph 英尺每秒 (ft/s) = 0.911344 ft/s 节 (kn) = 0.539957 kn 马赫 (Ma) = 0.000816 Ma 光速 (c) = 0 c
100 km/h = 27.777778 m/s because 1 km/h = 1/3.6 m/s by definition; knots, Mach and light speed are listed too.
Frequently asked questions
How is Mach defined?
Mach is the ratio of speed to the local speed of sound, so it has no fixed value. This tool uses the sea-level standard 340.29 m/s; at altitude the speed of sound drops to about 295 m/s.
What is a knot?
One nautical mile per hour: 1852 ÷ 3600 ≈ 0.514444 m/s.
Why include the speed of light?
For scale reference — 1 km/s = 3600 km/h and light travels at exactly 299792458 m/s.
What precision do the results have?
Every value is printed as Number(value.toFixed(6)). Use the exact factors shown when you need more digits.
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