Wind Speed: MPH to Knots

The speed of boats and aircraft is measured in knots.

The unit "knots" is a measurement of speed similar to miles-per-hour. Boats and aircraft worldwide use knots to measure their speed as opposed to mph and kilometers per hour.

Nautical Miles

Knots measure nautical miles per hour. A nautical mile is 6,076 feet; this is 796 feet longer than a regular mile. Nautical miles are still used worldwide because they are convenient when dealing with latitude and longitude.

Number of Miles in a Nautical Mile

A nautical mile is approximately 1.15 miles. Conversely, there are .87 nautical miles in a standard mile. Speed in knots should never be greater than the original speed in mph when converting the latter to the former.

MPH to Knots

Multiply the mph by .87 to convert it to knots. Multiply the mph by the amount of feet in miles -- and divide that by the amount of feet in a nautical mile -- to check your work

References

• NASA: Knots Versus Miles per Hour
• BIPM: The International System of Units