Convert Speed from Miles per hour to Knots (mph to knot)

Mile per hour to Knot Conversion Formula

Example

Let's convert 5 Mile per hour (mph) to Knot (knot).

Using the formula:

Therefore, 5 Mile per hour (mph) is equal to 4.3448829010609335068 Knot (knot).

How many miles per hour are in one knot? One Knot (knot) contains 1.150779 Miles per hour (mph) — the inverse of the factor above. Multiplying by 0.86897658021218670136 takes you from miles per hour to knots; multiplying by 1.150779 brings you back.

Put in words: one mile per hour equals 0.86897658021218670136 knots, so the mile per hour is the smaller unit of this pair. Converting between them never changes the amount of speed being measured — only the size of the unit you count it in.

Understanding Miles Per Hour (MPH)

Miles per hour (mph) is a standard unit of speed that measures the distance traveled in one hour.

It is primarily used in countries that use the imperial system of measurement, such as the United States and the United Kingdom, where it is commonly seen on road signs and speedometers.

How to Convert MPH to Other Speeds

When comparing speeds across countries, it helps to convert miles per hour (mph) into other common units.

One mile per hour equals:

• 1.609 kilometers per hour (km/h)
• 0.447 meters per second (m/s)
• 1.47 feet per second (ft/s)

These conversions are helpful for a wide range of applications, including international travel, science, and engineering.

Where Did MPH Come From?

The use of miles per hour became popular with the rise of cars and trains.

Before modern vehicles, travel was slow and didn't require precise speed measurement. As cars became common in the late 19th and early 20th centuries, MPH became the standard for speedometers in countries using the imperial system, providing drivers with a simple way to measure their speed.

Which Countries Use MPH?

While most of the world uses kilometers per hour (km/h) from the metric system, a few countries still officially use miles per hour.

The most well-known are:

• The United States
• The United Kingdom
• Liberia
• Myanmar

This is why many car speedometers show both MPH and km/h, making them useful for drivers in different parts of the world.

What Is a Knot and How Fast Is It?

A knot is a unit of speed used almost exclusively in maritime and aviation contexts.

One knot is equal to one nautical mile per hour.

• 1 knot = 1.15 miles per hour (mph)
• 1 knot = 1.852 kilometers per hour (km/h)

The abbreviation for a knot is "kt" or "kts" for the plural.

Why Is a Ship's Speed Called a "Knot"?

The term "knot" dates back to the 17th century, when sailors measured their ship's speed using a tool called a "chip log."

This device worked in a simple but clever way:

• A rope was tied with knots at regular intervals (every 47 feet and 3 inches).
• One end of the rope was attached to a piece of wood (the "chip") and thrown into the water behind the ship.
• As the ship moved forward, the rope would unspool. Sailors would count how many knots passed through their hands in 28 seconds, measured with a sandglass.

The number of knots they counted directly corresponded to the ship's speed in "knots."

How Is a Knot Connected to the Earth's Size?

A knot isn't a random measurement—it's directly linked to the Earth's circumference. To understand this, you need to know about the nautical mile.

A nautical mile is based on the Earth's coordinates of longitude and latitude. It is equal to exactly one minute (1/60th of a degree) of latitude.

Since a knot is one nautical mile per hour, it integrates seamlessly with all nautical and aeronautical charts.

This makes navigation and distance calculations much simpler for pilots and captains.

• 1 Nautical Mile = 1.852 kilometers (or 1,852 meters)
• 1 Nautical Mile = 6,076 feet

Why Do Planes and Ships Still Use Knots Today?

On land, we use miles per hour or kilometers per hour, but in the air and at sea, speed is measured in knots — and for good reason.

A knot is one nautical mile per hour, and a nautical mile is tied to the Earth's lines of latitude.

That direct link to the globe enables knots to work seamlessly with navigation charts, simplifying distance, travel time, and course calculations.

Using knots as a universal standard ensures that pilots, sailors, and air traffic controllers all speak the same language—an essential factor for global safety and coordination.

Mile per hour to Knot Conversion Table

Here are some quick reference conversions from Mile per hour (mph) to Knot (knot):