From meters per second (m/s)
- Meters per second to Kilometers per hourm/s → km/h
- Meters per second to Miles per hourm/s → mph
- Meters per second to Knotsm/s → kn
- Meters per second to Feet per secondm/s → ft/s
Speed conversion family
Speed unit conversions
Speed is the magnitude of the rate of change of distance with time and has dimension L T⁻¹; its coherent SI unit is meter per second (m/s).
Five named units
Unit and factor reference
| Unit | Symbol | Factor to base | Relationship | Definition and variant |
|---|---|---|---|---|
| meter per second | m/s | 1 | defined | Meter per second is the coherent SI unit of speed, representing one meter of distance per second of elapsed time. Named variant: Speed magnitude; direction is not represented. The base factor is exactly 1 by the family base-unit choice. |
| kilometer per hour | km/h | 0.2777777778 | approximate | One kilometer per hour is exactly 1000 m / 3600 s = 5/18 m/s. The exact factor is the repeating value 5/18. The preserved baseFactor 0.2777777778 is rounded and differs from the exact value by about 2.22×10⁻¹¹ m/s per km/h. |
| mile per hour | mph | 0.44704 | defined | One mile per hour uses the international mile and fixed hour: 1609.344 m / 3600 s = 0.44704 m/s exactly. Named variant: International mile per hour; not nautical mile per hour. The terminating base factor is exact. |
| knot | kn | 0.5144444444 | approximate | A knot is exactly one international nautical mile per hour: 1852/3600 m/s = 463/900 m/s. Named variant: International nautical mile per hour. The displayed symbol kn is conventional in this product; BIPM states no internationally agreed symbol exists. The exact factor is the repeating value 463/900. The preserved baseFactor 0.5144444444 is rounded and differs from the exact value by about 4.44×10⁻¹¹ m/s per knot. |
| foot per second | ft/s | 0.3048 | defined | One foot per second uses the international foot: 1 ft/s = 0.3048 m/s exactly. Named variant: International foot per second; not U.S. survey foot per second. The terminating base factor is exact. |
Every ordered pair
All 20 speed calculators
From kilometers per hour (km/h)
- Kilometers per hour to Meters per secondkm/h → m/s
- Kilometers per hour to Miles per hourkm/h → mph
- Kilometers per hour to Knotskm/h → kn
- Kilometers per hour to Feet per secondkm/h → ft/s
From miles per hour (mph)
- Miles per hour to Meters per secondmph → m/s
- Miles per hour to Kilometers per hourmph → km/h
- Miles per hour to Knotsmph → kn
- Miles per hour to Feet per secondmph → ft/s
From knots (kn)
- Knots to Meters per secondkn → m/s
- Knots to Kilometers per hourkn → km/h
- Knots to Miles per hourkn → mph
- Knots to Feet per secondkn → ft/s
From feet per second (ft/s)
- Feet per second to Meters per secondft/s → m/s
- Feet per second to Kilometers per hourft/s → km/h
- Feet per second to Miles per hourft/s → mph
- Feet per second to Knotsft/s → kn
Evidence and review status
This family is machine-reviewed-pending-human. Automated checks verify structure, factor parity and source references; they do not constitute human or specialist approval.
Family assumptions and limits
- This family converts non-negative speed magnitudes, not signed velocity vectors, acceleration, pace, or average-speed models.
- Mile per hour and foot per second use the international foot and international mile.
- Knot means exactly one international nautical mile per hour; the symbol kn is a CalcMotive display convention because the current SI Brochure notes that no internationally agreed unit symbol exists for the knot.
Authoritative references
- The International System of Units (SI), 9th edition, version 4.01; Bureau International des Poids et Mesures; Section 4, Table 8, pp. 140 to 141: nautical mile = 1852 m and knot = (1852/3600) m/s; note (k) says there is no internationally agreed symbol for either unit.; accessed 2026-08-07
- NIST Guide to the SI, Appendix B.8: Factors for Units Listed Alphabetically; National Institute of Standards and Technology; Alphabetical entries 'kilometer per hour', 'knot (nautical mile per hour)', and 'mile per hour'; factors to m/s.; accessed 2026-08-07
- NIST Handbook 44 (2026), Appendix C: General Tables of Units of Measurement; National Institute of Standards and Technology; Pages C-5 and C-9: international foot = 0.3048 m exactly and international mile = 1609.344 m exactly; combined with the SI Brochure's 3600-second hour.; accessed 2026-08-07