Convert knots to miles per hour and back. Shows km/h, m/s, Mach, Saffir-Simpson hurricane category, and speed comparison visuals.
The knots to mph calculator converts between nautical speed (knots) and statute miles per hour. One knot equals 1.15078 mph, so this tool is useful whenever marine or aviation speed reports need to be translated into the road-speed terms many readers use instinctively.
Alongside the core conversion, the calculator also shows km/h, m/s, ft/s, and Mach number. Presets cover maritime, aviation, and weather examples, and the comparison bar helps place a speed next to everyday references such as walking pace, highway traffic, and jet cruise speed.
The built-in Saffir-Simpson hurricane scale makes the page especially useful for weather interpretation. Forecast agencies often report sustained wind in knots, while public advisories and headlines often summarize the same storm in mph.
Maritime weather uses knots while US road and weather reports use mph. When a forecast says "sustained winds 64 knots," you need to know that means 74 mph — a Category 1 hurricane. This tool makes the conversion instant and keeps the storm-scale context visible so you can interpret wind speeds without doing the math by hand.
mph = knots × 1.15078. knots = mph ÷ 1.15078. 1 knot = 1 nautical mile/hour = 1.852 km/h.
Result: 64 kt = 73.6 mph = 118.5 km/h — Category 1 Hurricane
64 × 1.15078 = 73.65 mph. This is the minimum threshold for a Category 1 hurricane on the Saffir-Simpson scale.
Pilots report airspeed in knots indicated airspeed (KIAS) and true airspeed (KTAS). At altitude, thinner air means KTAS exceeds KIAS. A jet at FL350 might indicate 280 KIAS but fly at 480 KTAS. ATC and flight plans use knots exclusively.
Developed in 1971, the scale originally included storm surge and flooding estimates. Since 2010, it uses only wind speed: Cat 1 (64–82 kt), Cat 2 (83–95 kt), Cat 3 (96–112 kt), Cat 4 (113–136 kt), Cat 5 (≥137 kt). Major hurricanes (Cat 3+) cause the most destruction.
A cargo ship cruises at 12–15 knots (14–17 mph). A fast ferry does 30–40 knots (35–46 mph). Racing sailboats hit 30+ knots, and hydrofoils exceed 50 knots. The fastest naval craft (hovercraft) reach ~60 knots.
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This converter treats a knot as one nautical mile per hour and applies the fixed relationships 1 knot = 1.15078 mph and 1 knot = 1.852 km/h. Reverse conversion divides by the same factors, and the supporting outputs such as m/s, ft/s, and Mach are derived from the converted speed.
The hurricane category panel maps the converted sustained wind speed to the published Saffir-Simpson thresholds used by NOAA. Category labels on the page are informational only and reflect the sustained-wind range, not a full storm forecast.
Displayed values are rounded for readability, but the underlying conversion uses the calculator constants at full precision.
1 knot = 1.15078 mph. Conversely, 1 mph = 0.86898 knots.
Multiply by 1.15078, or simply add about 15%. Example: 100 knots × 1.15078 = 115.1 mph.
Nautical miles are based on Earth geometry (1 NM = 1 minute of latitude), making navigation math simpler. Aviation and maritime industries adopted knots for this practical advantage.
The Saffir-Simpson Hurricane Wind Scale classifies hurricanes into 5 categories based on sustained wind speed: Cat 1 (64–82 kt), up to Cat 5 (≥137 kt). It estimates potential property damage.
A tropical storm has sustained winds of 34–63 knots = 39–73 mph. Below 39 mph is a tropical depression; at 74 mph it becomes a hurricane.
A nautical mile is distance (1.852 km). A knot is speed (1 nautical mile per hour). "The ship travels at 20 knots" means 20 nautical miles per hour.