The knots to mph formula
To convert knots to miles per hour, multiply by 1.15078: mph = knots × 1.15078. For example, 50 knots × 1.15078 = 57.54 mph. A knot is one nautical mile per hour. To reverse it, use the mph to knots calculator.
The factor comes from the definition of the nautical mile: exactly 1,852 metres, against 1,609.344 metres for the statute mile. Dividing one by the other gives 1.15078, so every knot is about 15% faster than a mile per hour.
How to convert knots to mph
Enter a speed in knots and the calculator multiplies by 1.15078 to give miles per hour. This is handy for translating aircraft, boat, or wind speeds reported in knots into the mph used on road signs and weather apps.
For a quick estimate in your head, add roughly 15%: 20 knots is about 23 mph, and 60 knots is about 69 mph. The shortcut stays within half a mile per hour up to around 40 knots, which covers almost all marine and wind reporting.
Context helps when reading a forecast. A gentle breeze is 7–10 knots (8–12 mph), a small-craft advisory usually starts near 22 knots (25 mph), gale force begins at 34 knots (39 mph) and hurricane force at 64 knots (74 mph). Cruising airliners are typically quoted at 450–500 knots of true airspeed, which is roughly 518–575 mph.
If you are checking your work, the km/h to mph calculator gives you a second reference point.
Knots to mph reference table
| Knots | MPH |
|---|---|
| 10 knots | 11.51 mph |
| 50 knots | 57.54 mph |
| 100 knots | 115.08 mph |
| 200 knots | 230.16 mph |
The km to miles calculator is the natural next step once you have this figure.
Frequently asked questions
- What is 50 knots in mph?
- 50 knots equals 57.54 mph (50 × 1.15078).
- What is the knots to mph formula?
- mph = knots × 1.15078.
- What is one knot in mph?
- One knot equals about 1.15 mph.
- How do I convert mph back to knots?
- Divide by 1.15078, or use the mph to knots calculator.
- Is it wrong to say “knots per hour”?
- Yes. A knot already means one nautical mile per hour, so “knots per hour” describes acceleration rather than speed. The correct phrasing is simply “30 knots”, and the same applies when the figure is written as kt or kn.