Speed Converter
Convert speed between meters per second, kilometers per hour, miles per hour, feet per second, and knots using exact conversion factors.
How It's Calculated
Formula
\text{result} = \text{value} \times \text{mpsPerFromUnit} \div \text{mpsPerToUnit}Speed conversion means expressing the same rate of motion in a different unit. Every supported unit here converts through one canonical base unit, meters per second (m/s): the input value is first multiplied by its unit's exact m/s-per-unit factor, then that m/s value is divided by the target unit's m/s-per-unit factor. 1 km/h = 1 / 3.6 m/s exactly. 1 mph = 1609.344 m / 3600 s = 0.44704 m/s exactly, since the statute mile is internationally defined as exactly 1609.344 meters. 1 ft/s = 0.3048 m/s exactly. 1 knot = 1 nautical mile per hour, and the international nautical mile is defined as exactly 1852 meters, so 1 knot = 1852 / 3600 m/s exactly. The nautical mile used to define the knot is a different, larger unit than the statute mile used to define the mile and mph — the two must not be confused.
Worked Examples
Highway speed: 60 mph to km/h
- Convert to m/s: 60 mph x 0.44704 = 26.8224 m/s
- Convert m/s to km/h: 26.8224 m/s x 3.6 = 96.56064 km/h
- Result: 60 mph is approximately 96.56064 km/h
Maritime speed: 1 knot to mph
- Convert to m/s: 1 knot x (1852 / 3600) = 0.514444... m/s
- Convert m/s to mph: 0.514444... m/s / 0.44704 = 1.150779... mph
- Result: 1 knot is approximately 1.15078 mph
Frequently Asked Questions
Why convert through meters per second instead of directly between units?
Converting every unit to and from one canonical base unit (meters per second) means only one conversion factor per unit needs to be defined and verified, instead of a separate factor for every possible pair of units.
What's the difference between mph and knots?
Both measure distance per hour, but they use different distance units. Mph uses the statute mile (1609.344 m exactly), while the knot uses the international nautical mile (1852 m exactly) — a nautical mile is longer than a statute mile, so 1 knot is faster than 1 mph.
Is speed the same as acceleration?
No. Speed is distance per unit time (e.g., meters per second). Acceleration is the rate of change of speed per unit time (e.g., meters per second per second) and is not handled by this calculator.
Can I convert a negative speed?
Yes. This calculator treats speed as a generic numeric quantity and converts negative values the same way as positive ones, for mathematical conversion consistency.
What happens if I enter the same unit for both 'From' and 'To'?
The result equals the input value unchanged, since converting a unit to itself has a conversion factor of 1.