How to use this speed converter
Enter a speed and choose the source and destination units. Results update instantly. A negative value can represent direction in a signed calculation, but ordinary speed is the nonnegative magnitude of velocity.
How the calculation works
Speed is distance divided by elapsed time. A conversion must change both the distance unit and, where necessary, the time unit. One kilometer per hour equals 1,000 meters per 3,600 seconds.
A knot is one nautical mile per hour. The international nautical mile is exactly 1,852 meters, so one knot is approximately 0.514444 meters per second.
Formulas
Speed definition
General conversion
Worked examples
Convert 100 km/h to mph
100 kilometers per hour is approximately 62.1371 miles per hour.
Convert 10 m/s to km/h
10 × 3.6 = 36 kilometers per hour.
Common uses
Driving and travel
Compare road speeds and vehicle specifications stated in miles per hour or kilometers per hour without changing the physical rate.
Weather and marine navigation
Translate wind and vessel speeds among knots, meters per second, kilometers per hour, and miles per hour. Preserve whether the source reports sustained speed or gusts.
Sports and technical work
Convert running, cycling, machinery, airflow, or experiment rates after confirming that each value measures the same kind of speed.
Accuracy and limitations
Factors use exact international definitions for the meter, international foot, international mile, and nautical mile. Results are rounded only for display.
The tool converts numeric rates only. It does not account for direction, acceleration, wind, current, route distance, measurement uncertainty, or legal speedometer tolerances.
Frequently asked questions
Is speed the same as velocity?
Speed is magnitude only; velocity also includes direction. Negative inputs can encode direction but do not represent negative magnitude.
What is a knot?
One knot is one international nautical mile per hour, exactly 1,852 meters per hour.
Why multiply m/s by 3.6 for km/h?
There are 1,000 meters per kilometer and 3,600 seconds per hour, producing a factor of 3.6.
Does this account for wind or current?
No. It converts a stated numeric rate without changing its physical reference.
Is the speed converter free to use?
Yes. NumUtility is free, requires no account, and places no limit on ordinary calculations.
Are my entries stored?
No. The calculation runs in your browser. Values entered into the tool are not sent to NumUtility or saved by us.