How do you convert knots to miles per hour?

1 knot = 1 nautical mile per hour. 1 nautical mile = 1.15078 statute miles, so mph = knots × 1.15078. For example, 20 knots ≈ 23.016 mph.

How do you convert knots to km/h?

1 knot = 1.852 kilometers per hour. So km/h = knots × 1.852. This is exact according to the international nautical mile definition.

Why do ships and aircraft use knots?

Because knots are tied to nautical miles, which relate to the Earth's geometry and navigation. 1 minute of latitude ≈ 1 nautical mile, so speed in knots makes route planning simpler.

Knots to MPH & KMH Converter | Nautical Speed Converter

Convert speed

Speed (knots) kt

Decimal places

Result

MPH: –

KM/H: –

Uses: mph = knots × 1.15078, km/h = knots × 1.852 (exact).

Formulas and explanation

1 knot is defined as 1 nautical mile per hour. A nautical mile is standardized as 1.852 km or about 1.15078 miles. From this we get:

mph = knots × 1.15078
km/h = knots × 1.852

If you only need a quick mental estimate, you can use:

mph ≈ knots × 1.15
km/h ≈ knots × 1.85

Quick reference table

Knots	MPH	KM/H
5 kt	5.75 mph	9.26 km/h
10 kt	11.51 mph	18.52 km/h
15 kt	17.26 mph	27.78 km/h
20 kt	23.02 mph	37.04 km/h
25 kt	28.77 mph	46.30 km/h
30 kt	34.52 mph	55.56 km/h

FAQ

Why do ships and planes use knots?

Because nautical miles tie directly to latitude/longitude (1 NM = 1 minute of arc of latitude). This makes navigation and charting much simpler.

Is the factor 1.852 exact?

Yes — the international nautical mile is exactly 1.852 kilometers.

What about wind speed reports?

Meteorological and marine weather reports often quote wind in knots to match nautical practice. This converter gives you mph and km/h instantly.