Common conversions
1 m/s = 3.6 km/h · 1 mph = 1.6093 km/h · 1 knot = 1.852 km/h · 1 mph = 0.447 m/s
A quick mental trick: to go from m/s to km/h, multiply by 3.6. Knots (nautical miles per hour) are standard in aviation and shipping; mph on US/UK roads; km/h almost everywhere else.
Converting speed units
Speeds are defined relative to meters per second, so one value converts instantly to mph, km/h, m/s, knots and ft/s. Quick reference: 1 mph ≈ 1.609 km/h, and 1 knot ≈ 1.151 mph.