Numeric Differences in the U.S.
When visiting the United States, you will quickly notice that measurements work differently than in most other countries. The U.S. uses the imperial system rather than the metric system, and temperatures are measured in Fahrenheit instead of Celsius. Understanding these differences will help you navigate daily life more easily during your exchange program.
Measurements: Why Imperial and Not Metric?
While most of the world uses the metric system, the United States still primarily uses the imperial system for everyday measurements. This system was inherited from the British during the colonial era and has remained the standard despite global adoption of metric units.
In the U.S., distances are measured in miles, feet, and inches. Weight is measured in pounds and ounces. Liquids are measured in gallons, quarts, and fluid ounces. This can be confusing at first, but with a few key conversions in mind, you will adjust quickly.
Handy Measurement Tips
Here are some common conversions that will help you in everyday situations:
- 1 mile = 1.6 kilometers
- 1 foot = 30 centimeters
- 1 inch = 2.54 centimeters
- 3 feet = approximately 1 meter
- 1 kilogram = approximately 2 pounds
- 1 pound = approximately 454 grams
- 1 gallon = 3.8 liters
When you are grocery shopping, keep in mind that produce is typically priced per pound rather than per kilogram. Speed limits on roads are posted in miles per hour, and distances on road signs are shown in miles.
Tip: There are many free online tools and smartphone apps that can help you quickly convert between imperial and metric units. Try searching for “unit converter” in your phone’s app store, or use an online conversion calculator like World Wide Metric. Having a conversion tool on hand will make shopping, cooking, and traveling much easier.
Temperatures: Why Fahrenheit and Not Celsius?
Just like with measurements, the U.S. uses a different system for temperature. While most countries use Celsius, the United States uses Fahrenheit for weather reports, cooking, and everyday temperature references.
The Fahrenheit scale was developed by Daniel Gabriel Fahrenheit in 1724 and became the standard in many English-speaking countries. While the U.K. and other nations eventually switched to Celsius, the U.S. held on to Fahrenheit.
A comfortable room temperature in the U.S. is typically around 70°F, which is about 21°C. Here are some helpful temperature references:
- 32°F = 0°C (freezing point of water)
- 50°F = 10°C (cool weather, light jacket needed)
- 70°F = 21°C (comfortable room temperature)
- 85°F = 29°C (warm summer day)
- 95°F = 35°C (hot summer day)
- 212°F = 100°C (boiling point of water)
Temperature Conversion Formulas
If you want to convert temperatures yourself, here are the formulas:
Fahrenheit to Celsius: Subtract 32, then multiply by 5/9.
Example: 61°F minus 32 = 29, then 29 times 5/9 = approximately 16°C.
Celsius to Fahrenheit: Multiply by 9/5, then add 32.
Example: 20°C times 9/5 = 36, then 36 plus 32 = 68°F.
Important: When checking the weather forecast, remember that U.S. weather apps and news stations report temperatures in Fahrenheit. A quick shortcut to roughly estimate Celsius from Fahrenheit is to subtract 30 and then divide by 2. For example, 80°F minus 30 = 50, divided by 2 = 25°C (the actual answer is about 27°C, so this shortcut gives you a close estimate).
Similarly, when driving, remember that speed limits are in miles per hour. If you are used to kilometers per hour, a 65 mph speed limit is approximately 105 km/h.
