The Swiss Army Knife of conversions. Instantly convert Length, Weight, Volume, and Temperature between US Imperial and Metric systems.
Conversion Log
How to Use
The Every-Man’s Converter
Whether you are following a European recipe, traveling abroad, or working on a car, the divide between Imperial (US) and Metric units is a constant hurdle. This tool is designed to be the only converter you need bookmarking.
Mental Math Shortcuts
If you don’t have this calculator handy, here are some “close enough” estimates:
- Fahrenheit to Celsius: Subtract 30 and divide by 2. (e.g., $80°F - 30 = 50$, $50 / 2 = 25°C$).
- Miles to Kilometers: Multiply by 1.6. A 5k run is 3.1 miles.
- Pounds to Kg: Divide by 2. (100 lbs is roughly 45-50 kg).
Why do we have two systems?
The Imperial system evolved from ancient Roman units based on human anatomy (feet, thumbs/inches). The Metric system was designed during the French Revolution to be scientific and based on decimals (powers of 10).
The Math Behind It
Most conversions are simple multiplication, but Temperature requires an offset adjustment.
$$ T_{(°C)} = (T_{(°F)} - 32) \times \frac{5}{9} \quad \bigg| \quad V_{metric} = V_{imperial} \times \text{Factor} $$
Where:
- $T$ is Temperature.
- $V$ is Value (Length, Weight, or Volume).
- Factor changes based on the unit (e.g., 1.609 for Miles to Km).