Knots to MPH Converter
Convert knots (nautical miles per hour) to miles per hour, or mph to knots. 1 knot = 1852/1609.344 ≈ 1.150779 mph, exactly by definition.
Last updated: October 2026
Speed in mph
115.08 mph
Formula below · 2 sources (NIST, faa.gov) · Updated Oct 2026
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About this calculator
A knot is one nautical mile per hour. Both miles have exact metric definitions:
1 nautical mile = 1,852 m 1 statute mile = 1,609.344 m
so 1 knot = 1,852 ÷ 1,609.344 = 1.150779 mph, and 1 mph = 0.868976 knots. The calculator uses that exact ratio: 100 knots = 115.08 mph, and 65 mph = 56.48 knots. In metric units 1 knot = 1.852 km/h ≈ 0.514444 m/s.
Why aviation and shipping use knots
The nautical mile was based on one minute of latitude, so a speed in knots relates directly to distances read off a chart. Air traffic control, aircraft airspeed indicators, marine navigation and aviation weather reports (METAR wind) all use knots, while US road speeds use mph.
Airspeed is not ground speed
The conversion changes units only. A pilot's indicated or true airspeed in knots still differs from speed over the ground because of wind and altitude.
Knots, mph and km/h
Scroll sideways to see all columns →
| Knots | mph | km/h |
|---|---|---|
| 1 | 1.15 | 1.85 |
| 10 | 11.51 | 18.52 |
| 25 | 28.77 | 46.3 |
| 50 | 57.54 | 92.6 |
| 100 | 115.08 | 185.2 |
| 250 | 287.69 | 463 |
| 450 | 517.85 | 833.4 |
How to use
Pick the direction, enter the speed, and read the result rounded to 2 decimals. Example 1: 100 knots → 100 × 1.150779 = 115.08 mph, a typical light-aircraft cruise. Example 2: 65 mph → 65 × 0.868976 = 56.48 knots. Example 3: a 250-knot speed limit → 287.69 mph.
Frequently asked questions
How many mph is 1 knot?
1 knot = 1.150779 mph, because a nautical mile (1,852 m) is about 15% longer than a statute mile (1,609.344 m). To go the other way, 1 mph = 0.868976 knots.
Why do pilots and sailors use knots instead of mph?
The nautical mile came from one minute of latitude, so distances measured on navigation charts convert directly to time at a speed in knots. International aviation and maritime practice standardized on knots and nautical miles.
Is 'knots per hour' correct?
No. A knot already means nautical miles per hour, so 'knots per hour' would be a change in speed over time. Just say knots.
What is 100 knots in km/h?
100 × 1.852 = 185.2 km/h. The knot-to-km/h factor is exactly 1.852 because the nautical mile is defined as 1,852 m.
How fast is Mach 1 in knots?
It depends on air temperature. At sea level in the standard atmosphere (15 °C) Mach 1 is about 661 knots (761 mph); at a typical jet cruising altitude (−56.5 °C) it is about 573 knots.
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