Imperial vs. Metric System


3 minutes

Updated: 27 July 2020

Visiting the USA, you’ll first notice differences as soon as your plane lands. Why did the airport weigh your baggage in pounds? Waiting for a taxi outside, you’ll also notice the speed limit signs in MPH (Miles Per Hour). What’s all that about? The U.S. is one of the few countries globally which still uses the Imperial system of measurement, where things are measured in feet, inches, pounds, ounces, etc. Most countries use the Metric system, which uses the measuring units such as meters and grams and adds prefixes like kilo-, milli- and centi- to count orders of magnitude.

Why Imperial and Not Metric?

The Imperial System is also called The British Imperial because it came from the British Empire that ruled many parts of the world from the 16th to the 19th century. After the U.S. gained independence from Britain, the new American government decided to keep this type of measurement, even though the metric system was gaining in popularity at the time. We are one of the few countries in the world that still use this system, and first-time visitors can find it confusing. If you ask someone for directions, they will probably tell you something is a certain number of miles away. Or you may be told to move a few feet. But, whose feet?

A measuring tape with feet, inches, and meters
No need to break out the measuring tape - just read on!
Image courtesy of Pixabay

Handy Measurement Tips:

  • 1 mile equals 1.6 Kilometers
    A car speedometer showing miles and kilometers
    Many cars will show miles and kilometers on the speedometer
    Image courtesy of Unsplash
  • 1 foot (12 inches) is equal to 30 centimeters
  • 1 inch is about 25 millimeters or 2.54 centimeters
  • A 3-foot measurement is almost exactly 1 meter
    A measuring tape with feet, inches, and meters
    But keep in mind that it's not an exact 3:1 ratio!
    Image courtesy of Pexels
  • 1 Kilogram is just over 2 pounds
    Two blue 2 kilogram barbells next to an exercise ball, a scale, and workout shoes

    Image courtesy of Pixabay
  • 1 pound is about 454 grams
  • For U.K. visitors, 14 pounds = 1 stone

Fahrenheit vs Celsius

By the way, the temperature scales are different too. We didn’t want to make things too easy for you! Americans measure temperature in Fahrenheit, not Centigrade/Celsius. You may turn on the television and listen for the weather and hear that it is 70 degrees outside. No, you won’t pass out and be vaporized by the sun; 70 degrees Fahrenheit is actually very pleasant, about 21 degrees Celsius. Celsius has been used around the world from the mid 20th century, but again, Americans held fast to the original Fahrenheit system.

A thermometer showing Celsius and Fahrenheit
Many thermometers will show Celsius and Fahrenheit side-by-side.
Image courtesy of Pixabay
More conversions for temperature:

  • 0 degrees Celsius is equal to 32 degrees Fahrenheit. (The freezing point)
  • 24 degrees Celsius is equal to 75 degrees Fahrenheit. (A very pleasant day)
  • To convert Celsius (c) to Fahrenheit, use the formula (c x 1.8) + 32

There is no reason to expect that we will change over to the Metric System and Centigrade anytime soon. The chances that we will make the switch during your short-term stay in the United States are slim, so your best bet is to try to adjust as much as possible. Or, if you have a smartphone, you can download a conversion app. The company World Wide Metric has a comprehensive and easy to use conversion webpage.

One of the most interesting things about traveling is observing and learning about cultural differences that make countries unique. Even better, participating in an American internship allows you to do this while simultaneously furthering your career! If you found these facts interesting, you can check out a Career Training USA participant’s account of culture in the USA. And if you’re ready to experience the USA in person, consider applying to an American internship!

Matt Wallace

Matt Wallace is the Community & Digital Content Manager for the InterExchange Marketing team. He received a Master of Science in Global Affairs from New York University, and worked with the State Department and two New York organizations with missions to introduce young people to multiculturalism and international relations. He is excited to leverage this experience with InterExchange!

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