Knots and kilometers per hour
The knot is one nautical mile per hour: exactly 1.852 km/h. Ships, aircraft, and wind speeds in aviation and marine forecasts are measured in knots.
A kilometer per hour is 1,000 meters per 3,600 seconds: exactly 1/3.6 m/s. Speed limits, car speedometers and weather reports use km/h in most countries.
Worked example
Convert 30 kn: 30 × 1.852 = 55.56, so 30 knots is 55.56 kilometers per hour. Likewise 20 kn = 37.04 km/h.
Estimating in your head
Multiply by 1.9 for a quick figure; it is off by about 2.6%. For 30 kn that gives 57 km/h, against 55.56 exactly.
Going the other way
To convert kilometers per hour to knots, divide by 1.852 (or multiply by 0.539956803456).
How this works
km/h = kn × 1.852
1 kn = ≈ 0.5144444444 m/s and 1 km/h = ≈ 0.2777777778 m/s, both by definition, so the factor is their ratio: 1.852 exactly. Results drop binary floating-point noise beyond 15 significant digits and display at the precision you choose (6 significant figures by default). Copy result copies the full value.
Frequently asked
How many kilometers per hour are in a knot?
1 knot = 1.852 kilometers per hour, exactly. The value follows from the unit definitions, so it never changes.
How do I convert knots to kilometers per hour?
Multiply by 1.852. For example, 20 kn × 1.852 = 37.04 km/h.
What is 100 kn in kilometers per hour?
100 kn = 185.2 km/h. The table next to the converter lists more common values.
Is the result rounded?
Only on screen. The page computes with the exact definitions and removes floating-point noise past 15 significant digits; pick 3 to 12 significant figures, or use Copy result for the full value.
Sources
- NIST SP 811 Appendix B.8 — Factors for units listed alphabetically
- Federal Register 59-5442 (1959) — Refinement of values for the yard and the pound
- Wikipedia — Knot (unit)
Reviewed Oct 17, 2026 · test vectors fixtures/units/speed/knots-to-kmh/