640 kilometers per hour in knots

Conversion

640 kilometers per hour is equivalent to 345.572354211663 knots.^[1]

Conversion in the opposite direction

The inverse of the conversion factor is that 1 knot is equal to 0.00289375 times 640 kilometers per hour.

It can also be expressed as: 640 kilometers per hour is equal to $\frac{1}{0.00289375}$ knots.

Approximation

An approximate numerical result would be: six hundred and forty kilometers per hour is about three hundred and forty-five point five six knots, or alternatively, a knot is about zero times six hundred and forty kilometers per hour.

Units involved

This is how the units in this conversion are defined:

Kilometers Per Hour

"The kilometer per hour is a unit of speed, expressing the number of kilometres travelled in one hour. The unit symbol is km/h. Worldwide, it is the most commonly used unit of speed on road signs and car speedometers."

Wikipedia page of kilometers per hour

Knots

"The knot (/nɒt/) is a unit of speed equal to one nautical mile (1.852 km) per hour, approximately 1.151 mph. The ISO Standard symbol for the knot is kn. The same symbol is preferred by the IEEE; kt is also common. The knot is a non-SI unit that is accepted for use with the SI. Worldwide, the knot is used in meteorology, and in maritime and air navigation—for example, a vessel travelling at 1 knot along a meridian travels approximately one minute of geographic latitude in one hour. Etymologically, the term derives from counting the number of knots in the line that unspooled from the reel of a chip log in a specific time."

Wikipedia page of knots

Footnotes

[1] The precision is 15 significant digits (fourteen digits to the right of the decimal point).

Results may contain small errors due to the use of floating point arithmetic.