Unit converter
Knots to Miles per hour
Instant conversion in your browser — speed.
≈ 1.151 mph
Tip: enter the values one by one — 40 30 55 20 — and you get the total and the average.
1 kn = 1.150779448 mph
Quick table Knots → Miles per hour
| kn | mph |
|---|---|
| 1 | 1.150779448 |
| 5 | 5.75389724 |
| 10 | 11.50779448 |
| 25 | 28.7694862 |
| 50 | 57.5389724 |
| 100 | 115.0779448 |
| 500 | 575.389724 |
| 1,000 | 1,150.779448 |
All unit families
- Lengthmm · cm · m · km · in · ft · yd · miAlmost the whole world measures length in metres. The exceptions are narrow but stubborn: the United States uses feet and inches for everyday distances, and the United Kingdom still posts road signs in miles while selling timber in millimetres.
- Weight / Massmg · g · kg · t · oz · lb · stThe kilogram is the base unit, and until 2019 it was the last one still defined by a physical object: a platinum-iridium cylinder kept near Paris. It is now defined through the Planck constant, so it can be reproduced in any properly equipped laboratory.
- Temperature°C · °F · KTemperature is the one family here that is not a multiplication. Celsius and Fahrenheit have different zero points as well as different step sizes, so you need the formula: °F = °C × 9/5 + 32.
- Volumeml · l · m³ · gal · pt · fl oz · cupThis is the family where the same word means two different amounts. American and British measures share their names but not their sizes, and a recipe that ignores the difference will not work.
- Aream² · km² · ha · ft² · acAreas are where a linear conversion quietly goes wrong. One metre is 3.28 feet, but one square metre is 10.76 square feet — the factor is squared. Converting the sides and forgetting the square is the single most common mistake in this family.
- Times · min · h · d · wk · mo · yrSeconds, minutes, hours, days and weeks convert exactly. Months and years do not, and no converter can make them.
- Digital storagebit · B · KB · MB · GB · TBDigital storage has two conflicting definitions of the same prefixes, and almost every confusion about file sizes comes from that.
About this conversion
A knot is one nautical mile per hour, and a nautical mile is one minute of latitude — one sixtieth of a degree. That is the whole reason the unit exists: on a chart, an hour at one knot moves you exactly one minute up the latitude scale printed along the edge, so a navigator could measure speed with the same ruler used for position. Aviation kept it for the same reason. The conversion is × 1.15078 to miles per hour.
⚠️ The mistake worth avoiding: knots to mph is × 1.15, knots to km/h is × 1.85. Confusing the two turns a 20-knot wind into either 23 or 37, and those are very different afternoons.
| Knots | mph | km/h | What it means at sea |
|---|---|---|---|
| 4 kn | 4.6 | 7.4 | light breeze, small wavelets |
| 10 kn | 11.5 | 18.5 | gentle breeze, crests start to break |
| 12 kn | 13.8 | 22.2 | moderate breeze, first whitecaps |
| 15 kn | 17.3 | 27.8 | moderate breeze, frequent whitecaps |
| 16 kn | 18.4 | 29.6 | the top of that band |
| 20 kn | 23.0 | 37.0 | fresh breeze, moderate waves, spray |
| 25 kn | 28.8 | 46.3 | strong breeze, larger waves |
| 26 kn | 29.9 | 48.2 | still strong breeze |
| 30 kn | 34.5 | 55.6 | near gale, foam blowing in streaks |
The last column is the part a converter usually leaves out, and it is normally what you actually wanted to know. A wind in knots is not the same experience as the same number in mph on land, because water shows it: at 10 knots the crests only begin to break, at 15 the whitecaps are everywhere, and somewhere around 20 the spray starts coming off them. Small sailing boats begin reefing in that region, and a forecast of 25–30 knots is the point where most people with a choice stay in the harbour.
One more thing the number hides: boat speed in knots is speed through the water, not over the ground. A boat doing 6 knots against a 2-knot current is covering 4 knots of chart — which is why an arrival time worked out from the speedometer is optimistic on the way out and pessimistic on the way back.
Frequently asked questions
How do you convert knots to miles per hour?
To go from kn to mph: multiply by 1.150779448 (1 kn = 1.150779448 mph). Example: 3 kn = 3.452338344 mph. The converter above runs the math live as you type.
How much is 2 knots in miles per hour?
2 kn equals 2.301558896 mph. For other values, use the quick table or type your own number into the converter.
What are knots (kn)?
The knot is one nautical mile per hour (1.852 km/h), the speed unit of ships, aircraft and wind at sea — named after the knotted rope sailors once used to gauge speed. A 20-knot wind is about 37 km/h.
What is miles per hour (mph)?
Miles per hour is the speed unit of US and UK roads. A 70 mph motorway limit equals about 113 km/h; hurricanes are also classified by mph wind speeds.