How Unit Conversion Works
Every conversion is a two-step calculation: multiply your value by the source unit's factor to reach a base unit, then divide by the target unit's factor. For length the base is meters; for weight it is kilograms. Because the factors are internationally defined constants, the only limit on precision is how many digits you type.
Metric vs. Imperial
Metric units scale by powers of ten (1000 meters in a kilometer), while imperial units use irregular ratios (5280 feet in a mile, 16 ounces in a pound). That is why converting between the systems trips people up โ and why a converter beats mental arithmetic for anything beyond rough estimates.
The Temperature Exception
Temperature is the odd one out: Celsius, Fahrenheit, and Kelvin have different zero points, so you cannot convert with a single multiplier. The formulas are ยฐF = (ยฐC ร 9/5) + 32 and K = ยฐC + 273.15. This tool applies the offset math for you.
Everyday Conversions
Cooking (cups to milliliters), travel (miles to kilometers), weather (ยฐF to ยฐC), and DIY projects (feet to meters) are the conversions most people look up. Bookmark this page and the answers are one tap away.
Doing math with the converted numbers? Use our four-function calculator.