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Knots to MPH

Knots (kn) to miles per hour (mph).

Result34.5234mph

Precision (significant figures)

Formula

mph = kn × 1.15078

1 kn = 1.15078 mph

mph = knots × 1.15078. A knot is one nautical mile per hour, and a nautical mile is 1,852 m against 1,609.344 m for a statute mile. So 10 knots is 11.5078 mph and 30 knots is 34.5234 mph.

Formula

mph = kn × 1.15078

Worked example

  1. Start with 30 kn.
  2. Multiply by 1.15078 (mph per kn): 30 × 1.15078 = 34.5234 mph.

Knots to mph chart

Knots (kn)Miles per hour (mph)
11.15078
55.7539
1011.5078
1213.8094
1517.2617
2023.0156
2528.7695
3034.5234
3540.2773
4046.0312
5057.539
100115.078
150172.617
250287.695
450517.851
500575.39

When you need this conversion

US marine forecasts, boating, hurricane advisories (which give both), and aviation when you think in mph.

Quick reference

  • 1 kn = 1.15078 mph
  • 10 kn = 11.5078 mph
  • 20 kn = 23.0156 mph
  • 30 kn = 34.5234 mph
  • 100 kn = 115.078 mph

Rule of thumb

Add 15%: 40 knots is about 46 mph (exact: 46.03). Good enough for weather and boating.

Common mistakes

Treating knots and mph as equal. The 15% gap matters for fuel planning and storm strength.

Confusing nautical and statute miles on charts. Nautical charts measure distance in nautical miles; road maps use statute miles.

For kilometers per hour, use knots to km/h.

Questions

How fast is 1 knot in mph?

1.15078 mph.

How fast is 20 knots in mph?

23.0156 mph.

Is a knot faster than a mile per hour?

Yes, by about 15%.

How fast is 100 knots?

115.078 mph, about the cruising speed of a small single-engine plane.

Sources

Last reviewed 2026-09-24. How we check values · Report a problem with this page