Convert a speed reading
- Enter a nonnegative speed and choose its distance/time unit.
- Select the target unit and convert.
- Review the metres-per-second value and factor, then copy or download.
Distance and time together
60 mph = 96.56064 km/h = 26.8224 m/s. One metre per second is 3.6 km/h. A knot is one international nautical mile per hour, so 20 knots = 37.04 km/h.
The calculation is speed × source factor in m/s ÷ target factor in m/s. One mile is 1609.344 m, one nautical mile is 1852 m, and one hour is 3600 s. Factors use these full definitions rather than rounded intermediate km/h or knot factors. Reference: NIST’s velocity conversion table.
| Unit | Metres per second per unit |
|---|---|
| Metres per second (m/s) | 1 |
| Kilometres per hour (km/h) | 0.2777777777777778 |
| Miles per hour (mph) | 0.44704 |
| Feet per second (ft/s) | 0.3048 |
| Feet per minute (ft/min) | 0.00508 |
| Knots (nautical miles/hour) | 0.5144444444444445 |
| Centimetres per second (cm/s) | 0.01 |
| Kilometres per second (km/s) | 1000 |
Limits and privacy
Nonnegative source speeds up to 10¹⁵, with arithmetic underflow rejected. This converts speed magnitude without direction, acceleration or physical-motion modelling. Optional one-kilometre and one-mile travel times assume constant speed without stops: seconds = distance in metres ÷ speed in m/s. Pace input, arbitrary trip distances, rotations per minute and Mach number are not supported. Mach depends on the local speed of sound, so it cannot use a single universal factor.
Displayed values use up to 12 significant digits and six decimal places or scientific notation for extremes. CSV retains floating-point numeric results and may show rounding effects. Speed inputs stay in browser memory, with no upload or saved measurements. Live conversion waits 300 ms. The all-units table and CSV compare all eight units for the same speed. Swap keeps the entered number; result reuse reverses direction with the unrounded converted value. Those actions, examples and Reset offer one Undo step; typing discards action history. Reset clears results and restores 60 mph to km/h. Travel times are rounded for display; the selected-conversion CSV includes numeric seconds per kilometre and per mile. Empty time cells mean zero speed or a numeric precision limit, while the primary speed conversion remains available.
Is a knot just another mile per hour?
A knot uses nautical miles; mph uses international land miles. They have different distance definitions.