About Speed Converter
Speed Converter translates a rate of movement between five units: metres per second, kilometres per hour, miles per hour, knots and feet per second. It handles the everyday switch between metric road speeds and the miles per hour used in a handful of countries, and the knots and metres per second that appear in aviation and science.
The factors are standard international definitions, so a mile per hour is 0.44704 metres per second and a knot is about 0.514444 metres per second, the latter being one nautical mile per hour. Because the relationship between km/h and m/s is a clean division by 3.6, those two convert exactly, while the imperial-based units carry the decimal tails that come from the definitions of the mile and the foot.
The converted figure is returned without a unit label, the unit being whichever you picked in the second selector. Speeds span a wide range — from a walking pace to orbital velocity — so it is worth glancing at the order of magnitude to be sure the units you chose were the ones you intended.
How to use Speed Converter
- 1 Enter the speed to convert.
- 2 Select the unit the speed is in, such as km/h or mph.
- 3 Select the target unit and run the tool.
Frequently asked questions
What exactly is a knot?
One nautical mile per hour, which works out to about 0.514444 metres per second, or roughly 1.852 kilometres per hour. Aviation and marine navigation use knots because they pair naturally with nautical miles and degrees of latitude.
How do I convert km/h to m/s quickly?
Divide by 3.6. Because an hour has 3600 seconds and a kilometre has 1000 metres, the ratio is exactly 3.6 with no rounding, so 36 km/h is exactly 10 m/s.
Is mph the same as the UK and US mile?
Yes. Both countries use the international mile of 1609.344 metres, so a mile per hour means the same thing in each. The unit is only ambiguous if someone is referring to a historical mile, which this tool does not use.
Can it convert a pace, like minutes per kilometre?
Not directly — this tool works with speed units, not pace units, so minutes per kilometre cannot be entered. The Running Pace Calculator handles pace and converts it to speed for you.
Free, online, and private
Free to use
Speed Converter is completely free. There is no account to create, no login, and no hidden charge or usage limit.
Runs online in your browser
It is a free online tool that runs entirely in your browser. Nothing to download or install — open the page and start using it right away.
Your data stays private
All processing happens locally on your device. Your input is never uploaded, stored, or tracked, so it never leaves your browser.
How Speed Converter behaves in detail
These are the specifics of this implementation — the exact ranges, defaults and fixed settings you are working with.
| Parameter | Value |
|---|---|
| Units covered | 5 — m/s, km/h, mph, knots and ft/s |
| Conversion basis | metre per second |
| Anchors | 1 km/h = 0.277778 m/s · 1 mph = 0.44704 m/s · 1 knot = 0.514444 m/s · 1 ft/s = 0.3048 m/s |
| Arithmetic applied | (value × from-unit factor) ÷ to-unit factor |
| Result precision | 8 decimal places, from a starting Value of 1 |
| Default pair | km/h → mph |
Compiled from the implementation of this tool and checked against it by itoolnet.
What Speed Converter does not do
Knowing the edges of a tool saves more time than another list of its features. These are the cases where it will not do what you might expect.
- Two factors are truncated decimals rather than exact fractions. Kilometres per hour is stored as 0.277778 where 1/3.6 is 0.2777777…, and the knot as 0.514444 where 1,852/3,600 is 0.5144444…. The error sits far below the eight decimals printed, but it is carried through every conversion.
- Five units is the complete list. Kilometres per minute, miles per minute, feet per minute and Mach number are all absent, and Mach could not be a fixed factor in any case because it depends on air temperature and pressure — this table has no place to put those.
- Speed is treated as a bare ratio. There is no distance-and-time entry such as "100 km in 1 h 20 min", no pace output in minutes per kilometre, and no direction or velocity component, so a vector problem cannot be expressed here at all.
Tested and documented by itoolnet, the team that builds and maintains this site.