What is the actual difference between Statute Miles vs. Nautical Miles? And even more important: How can you convert nautical miles to miles and miles to nautical miles?
Well, the math is simple:
- A statute mile is 5,280 feet in length.
- A nautical mile is around 6,076.11549 feet in length.
But to make things even easier for you, I have gone ahead and made a simple converter you can use to switch between statute miles and nautical miles whenever you have the need:
Even though the calculation isn’t really all that precise, people that convert from statute miles to nautical miles will use a factor of 1.15.
If you were to multiply 5,280 feet X 1.15, you’d get 6,072 feet, which is approximately 4.11549 feet less than 1 nautical mile. You can also add 4.1 feet for every statute mile that will be converted, which makes the new formula somewhere along the line of 5280 feet x 1.15 plus the additional 4.1 feet, then divided by 6,076.1 feet, which would result in 1 nautical mile.
People also use the factor 1.15 to convert nautical miles to statute miles, but this, again, isn’t the most precise formula out there.
So if you were to divide 6076.1 by 1.15 you would get 5,283 feet, which is 3.565 feet more than 1 statute mile. You will get more precise answers if you were to use Bowditch’s Table 20, or another precomputed table for that matter.
When doing quick calculations for reasons like small talk and a less precise answer will do, then just use the math below:
- nautical miles x 1.15 = statute miles
- statute miles x .87 = nautical miles
You will often hear people saying that 8 statute miles are equal to 7 nautical miles. When looking o easily convert nautical to statute, you can just multiply nautical miles by 8 and then just divide whatever you get by 7. To do the conversion backward just do everything in reverse. You multiply statute miles by 7 and then divide the resulting number by 8.
The Nautical Mile is considered one minute of latitude or 1/60th of a degree. When working with any charts, make sure you know exactly what measurement has been used. Most charts will use these four common measures of distance:
- Even though meters weren’t very used in the past in the U.S., newer charts have started to use this metric more and more. Other countries all over the world have always used meters as a metric on charts.
- On charts a mile long or less, yards are most often used as a metric.
- On charts of inland areas like the Great Lakes and Intracoastal Waterway statute miles are usually used.
- Charts of coastal and ocean waters will usually use nautical miles.
Nautical Mile Understanding
Nautical miles are the metric people use for distances that have to be traveled through the water. A nautical mile is equal to 1.1508 statute (land-measure) miles, which makes it slightly longer. As I said before. one nautical mile represents one minute of latitude, which correlates nautical miles to the Earth’s latitude and longitude coordinates.
At this point, you might ask why would people feel the need to have different measurement systems for marine navigation. When it comes to long-distance travel, the curvature of the Earth is becoming a very important factor for accurate measurement, which makes using longitude and latitude more practical. Mariners will have an easier time measuring distance using nautical miles because nautical charts make use of longitude and latitude. It’s also common for air and space travel to use longitude and latitude for navigation, which means they also use nautical miles as a way of measuring distances.
It’s not uncommon for people to ask if along with the nautical mile, there’s also a nautical kilometer. The short answer is no, there is not. The nautical mile is an international metric, used all around the world. This measurement was made official at set to be exactly 1.852 km in 1929 by the institution that is currently known as the International Hydrographic Organization. Even though the measurements used by the UK and the US were just slightly different at that point, in 1954 the US moved on to using the international nautical mile, followed by the UK in 1970.
Knots are a measurement that is used for speed and not length. The knot represents 1.15 statute miles per hour or one nautical mile per hour.
The term knot originates from the 17 century. At that point, sailors used it to measure the speed of a ship with the help of a device known as a common log. The common log was a pretty simple device made by just a rope with knots set at regular intervals, which was attached to a pie-like wood piece. It was used by mariners who would lower the whole wood piece into the water and then just let it float freely behind the ship. After a certain amount of time, measured with something like an hourglass, they’d just found the knots between the piece of wood and the shop.