Conversion Calculator
Use this conversion calculator to convert common units between US customary and metric, including temperature.
What Is a Conversion Calculator?
A conversion calculator changes a measurement from one unit to another, such as miles to kilometers or pounds to kilograms. It is especially useful in the United States, where everyday measurements use the US customary system while science, travel and many products use metric.
How to Use This Conversion Calculator
Enter a value, choose a conversion from the list and the result appears immediately. The table below the result shows the reverse conversion for the same number.
Common Conversions
- Length: 1 inch is 2.54 centimeters, 1 foot is 0.3048 meters and 1 mile is 1.609 kilometers.
- Weight: 1 pound is 0.4536 kilograms and 1 ounce is 28.35 grams.
- Volume: 1 US gallon is 3.785 liters and 1 cup is about 236.6 milliliters.
- Area: 1 square foot is 0.0929 square meters and 1 acre is 0.4047 hectares.
- Speed: 1 mph is 1.609 km/h.
How to Convert Fahrenheit to Celsius
Subtract 32 and multiply by 5/9. For example, 68 degrees F is (68 - 32) x 5/9 = 20 degrees C. To go the other way, multiply Celsius by 9/5 and add 32. Body temperature of 98.6 F is 37 C.
US Customary vs. Metric
The US customary system uses inches, pounds and gallons, while the metric system uses meters, kilograms and liters and is based on powers of ten. Note that the US gallon differs from the imperial gallon used in the UK, so check which one a recipe or product uses.
Tips for Accurate Conversions
Keep extra decimals during multi-step work and round only at the end. For cooking, weigh ingredients in grams when you can, since cup measurements vary with how an ingredient is packed.
Frequently Asked Questions
How many kilometers are in a mile?
One mile equals about 1.609 kilometers.
How many pounds are in a kilogram?
One kilogram is about 2.2046 pounds. Use the reverse line in the results.
Why is temperature different?
Temperature scales have different zero points, so it needs a formula and not just a multiplier.
Results are rounded to 8 significant digits.