Reference table

Speed: km/h, m/s, mph and knots

Road traffic uses km/h, physics uses m/s, shipping and aviation use knots. The table shows the same speed in all four units.

Speed: km/h, m/s, mph and knots
km/hm/smphkn
10.27777778 m/s0.62137119 mph0.5399568 kn
51.38888889 m/s3.10685596 mph2.69978402 kn
102.77777778 m/s6.21371192 mph5.39956803 kn
205.55555556 m/s12.42742384 mph10.79913607 kn
308.33333333 m/s18.64113577 mph16.1987041 kn
5013.88888889 m/s31.06855961 mph26.99784017 kn
8022.22222222 m/s49.70969538 mph43.19654428 kn
10027.77777778 m/s62.13711922 mph53.99568035 kn
13036.11111111 m/s80.77825499 mph70.19438445 kn

One knot is exactly 1.852 km/h, that is one nautical mile per hour. 100 km/h is about 62.14 mph and 53.996 knots. m/s and km/h differ by a factor of 3.6.

Sources

BIPM SI BrochureSI base units, prefixes and official SI context.NIST Guide to SI Appendix BNIST conversion-factor method and non-SI factors.

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