People have been trying to measure items since ancient times. In the modern era, the imperial and metric systems are the two most commonly used and standard systems. These systems have become an established and essential part of every country and are used on a regular basis in both domestic and commercial settings.
There are various benefits to converting between the imperial and metric systems. You may be travelling in a country or reading a document that uses a different measurement system than your own country. You may struggle to comprehend the distance or weight of something because you are not familiar with the other measuring system.
It's helpful to understand the conversion rate between the imperial and metric measurement systems. Kilometers and miles are commonly used in everyday life, which means that they are a good starting point to understanding the relationship between the two measurement systems.
In this guide, we'll look at how many kilometers are in a mile and how you can convert between the two unit measurements.
A kilometer (km) is a unit of length that can be used to measure distance. The kilometer is part of the metric measurement system, which countries worldwide have largely adopted. There are approximately 1.609 kilometer in a mile, which is the imperial unit equivalent. There are approximately 0.621 miles in one kilometer.
The name originates from the Greek prefix kilo, which translates to 'one thousand'. 'Meter' comes from the Greek word 'metron', which means 'a measure'. As the name suggests, there are one thousand meters in a kilometer, which is why this unit is often used to measure long distances.
Some examples of distances that are often measured in kilometers are:
- distance between two cities
- distance travelled during a run
- speed limits (how many kilometers travelled in an hour)
It takes about 12 minutes to walk a kilometer if you are walking at a steady pace. On average, an active individual can take between five and ten minutes to run a kilometer. Professional runners can usually run one kilometer in under four minutes. The fastest record for a kilometer run, which was set by Kenyan runner Noah Ngeny in 1999, is two minutes and 11 seconds.
One kilometer is equal to 0.6214 miles. One mile equals 1.609 kilometers.
The conversion table below shows the conversion rate from the metric to the imperial system:
| Metric | Imperial |
| 1 millimetre [mm] | 0.03937 inches [in] |
| 1 centimetre [cm] | 0.3937 inches [in] |
| 1 meter [m] | 1.0936 yards [yd] |
| 1 kilometer [km] | 0.6214 miles [mi] |
The conversion table below shows the conversion rate from the imperial to the metric system:
| Imperial | Metric |
| 1 inch [in] | 2.54 centimeter [cm] |
| 1 foot [ft] | 0.3048 meter [m] |
| 1 yard [yd] | 0.9144 meter [m] |
| 1 mile [mi] | 1.6093 kilometer [m] |
| 1 nautical mile [nmi] | 1.852 kilometer [km] |
Conversion charts are generally the easiest and quickest way to work out how many miles are in a set number of kilometers and vice versa. However, you can also use a simple multiplying or division equation to calculate the conversion.
You need to divide the distance by 1.609 to calculate the conversion from kilometers to miles. For example:
10km ÷ 1.609 = 6.213
10km = 6.213 miles
To convert miles to kilometers, you need to multiply the distance in miles by 1.609.
For example, 20m x 1.609 =32.18
20m = 32.18km
A nautical mile is a distance unit used for sea and air navigation. A single nautical mile is approximately 1,853 meters or 1.853 kilometers, which equates to 6,080 feet. There are approximately 0.53996 nautical miles in one kilometer. You can multiply 0.53996 by the number of kilometers you have to calculate the distance in nautical miles. Alternatively, you can multiply the given number of nautical miles by 1.853 to calculate the distance in kilometers.
There is a difference between land miles and nautical miles because the Earth is an imperfect sphere and is slightly flattened at the poles. The measurement is based on the earth's circumference and is equal to one minute of latitude.
An easy way to quickly convert kilometers and miles is using an online calculator. This is handy when the numbers you're working with have decimal places, as they can be harder to mentally calculate than whole numbers.
It can be difficult to mentally divide or multiply by 1.609 to convert between kilometers and miles. However, you can use different techniques that can help you to estimate the answer by using simplified equations. For example, five miles is approximately eight kilometers. You can therefore divide by five and multiply by eight to calculate the distance in kilometers instead of miles.
Alternatively, you can halve the given number of kilometers, take a quarter of the halved result and add the two together. For example:
144 km ÷ 2 = 72
72 ÷ 4 = 18
72 + 18 = 90
144km is approximately 90 miles using this calculation method. Using the correct actual rate, 144km actually converts to 89.4775 miles, which isn't too far off the estimate.
The majority of the world, bar the United States, Liberia and Myanmar, use the metric system. The metric system measures vehicle speed in kilometers per hour (kph).
The United States uses US customary units as the main measurement system in the country. This system is based on the imperial system and so, therefore, uses inches, feet, yards and miles to measure distance.
The United Kingdom has officially adopted the metric system, but the imperial system is also frequently used too. 9% of countries, which includes the UK and US, use mph (miles per hour) as a unit of measurement. The remaining 81% of countries use kph (kilometers per hour) to measure the speed that a vehicle is travelling at.
Speed limits vary around the world, with some countries allowing drivers to travel at any speed that they like on certain roads. For example, Germany's Autobahns have no speed limit in certain sections, although the government recommends a maximum of 130kph (80 mph).
Kilometers are generally used to measure long distances, such as the length of a road or the distance between two locations. Meters are used for smaller measurements, such as the size of rooms or height.
Many countries use the metric system, which makes it an almost universal measurement system. For this reason, most companies prefer to use the metric system as it makes it easier to trade on the international market. It prevents any confusion because everyone understands what is meant by kilometers, meters, and centimetres. This ensures that there is no confusion or errors when trading with people from different countries.
The metric system is also arguably easier to understand because it is based on scientific constants rather than everyday items like the imperial units. The metric system uses decimal numbers, whereas the imperial system uses varying bases, such as three, eight and twelve. This can make it more difficult to use the imperial system in complex calculations.
There are 5,280 feet in a mile, which is more difficult to remember than 1,000 meters in a kilometer. You can therefore convert between meters and kilometers more easily than you can between feet and miles.
The International System of Units (SI) incorporates seven base units that are the standard measurement unit that all other units in the SI are based on. The meter is the base unit used to measure length, which is what the kilometer is based on. It is a base unit that is recognized in the vast majority of countries worldwide
The table below shows the seven units, their symbols and what they are used to measure.
| Unit | Symbol | Measure |
| second | s | time |
| meter | m | length |
| kilogram | kg | mass |
| ampere | A | electric current |
| kelvin | K | thermodynamic temperature |
| mole | mol | amount of substance |
| candela | cd | luminous intensity |
There are 1.609 kilometers in a mile and 0.6214 miles in a kilometer. You can convert miles to kilometers and vice versa by using an online converter. Alternatively, you can convert kilometers to miles by dividing the length value by 1.609. Converting miles to kilometers uses the same formula in reverse – you can multiply the length value by 1.609.
Along with meters, kilometers are used to measure distance and length. However, meters are used to measure smaller distances, whilst kilometers are better for measuring larger distances, such as the distance a vehicle travels or the distance between two countries.
Over 80% of the world uses the metric system and therefore kilometers to measure length and distance. Countries such as the US and UK are in the minority and set speed limits in miles per hour rather than kilometers per hour. Many people consider the metric system easier to understand and better for trade as most countries use it.
