Knots to mph converter
This knots to mph converter turns knots into miles per hour as you type, for a boat speed read off a chartplotter, a wind figure from a marine forecast or an airspeed given by a pilot.
Formula: M/h ≈ kts × 1.15078 10 × 1.15078 ≈ 11.50779448
How the knots to mph converter does the math
Type a speed in knots and the miles per hour show up next to it. The page opens on 10 knots, which the knots to mph converter reads as 11.5078 mph. The round button flips the direction, or you can jump to the page for turning miles per hour into knots. The list underneath adds km/h, meters per second and Mach.
A knot is one nautical mile per hour. The international nautical mile is exactly 1,852 meters, so a knot is 1.852 km/h, while the statute mile on US road signs is 1,609.344 meters. Dividing one by the other gives 1.150779: multiply knots by that figure to get mph. NIST lists the knot at 0.514444 m/s and the mile per hour at 0.44704 m/s, the same ratio. Knots to miles per hour is a fixed conversion, rounded only on screen.
Mental shortcut: add 15 percent to the knots. 20 knots plus 3 makes 23 mph, against 23.02 exactly, and 40 knots becomes 46 mph. For a figure that goes into a logbook or a report, read the exact result instead.
Common values
| kts | M/h |
|---|---|
| 1 | 1.1508 |
| 5 | 5.7539 |
| 10 | 11.5078 |
| 15 | 17.2617 |
| 20 | 23.0156 |
| 25 | 28.7695 |
| 30 | 34.5234 |
| 35 | 40.2773 |
| 40 | 46.0312 |
| 50 | 57.539 |
| 64 | 73.6499 |
| 100 | 115.0779 |
Boats, storms and aircraft in knots
On a boat, the speed log, the chartplotter and the marine forecast usually speak in knots. A sailboat making 6 knots moves at 6.9 mph, and a 15-knot breeze blows at 17.3 mph, figures the knots to mph converter puts in road terms. The unit comes from navigation: one nautical mile spans one minute of latitude, and the US adopted the international nautical mile in 1954.
Hurricanes are tracked in knots too. The National Hurricane Center classes a storm as a hurricane from 64 knots, which is 73.65 mph by the math and 74 mph in its public advisories, and as a tropical storm from 34 knots, or 39 mph. Put a forecast value into the knots to mph converter to compare it with the figures on the news.
Pilots and air traffic controllers also use knots for airspeed and wind. A flight tracker showing 450 knots of ground speed means about 518 mph. Airport weather reports give wind in knots as well, so a 12-knot crosswind is 13.8 mph. Instruments often shorten the unit to kt or kts, and kts to mph uses the same factor. For distances rather than speeds, the km to miles converter also lists the nautical mile.