Knots to miles per hour converter

Knots describe nautical miles per hour and are used for marine and aviation speeds. They are a speed unit already, so knots per hour would mean a change in speed. Wind and current can also make speed through water differ from speed over ground.

One knot is about 1.150779448 miles per hour. One knot is one nautical mile (exactly 1,852 m) per hour.

Multiply the number of knots by 1.150779448. For example, 20 kn × 1.150779448 = 23.015589 mph. To go the other way, divide by 1.150779448.

Multiply by 1.15. That is 0.06773% low of the exact factor 1.150779448, so 20 kn comes out as 23 mph instead of 23.0156.

Accuracy depends on your inputs and the method's assumptions. Decimal arithmetic uses 50 significant digits, but estimates, numerical methods and source data can be less precise; the displayed rounding does not remove those limits. It is checked against 3 worked examples whose answers come from independent sources; for example, “20 kn to mph” is checked against Exact-fraction computation from the legal unit definitions (scripts/gen-pairs.py, Python fractions).

NIST SP 811 (2008), Guide for the Use of the International System of Units, Appendix B; NIST Handbook 44, Appendix C: General tables of units of measurement; BIPM, The International System of Units (SI Brochure), 9th edition.