Conversions

Conversion tools turn everyday measurements into the unit you need — length, weight, temperature, volume and power.

Each converter uses a documented definition rather than a rounded rule of thumb: the international inch is 2.54 cm, the avoirdupois pound is 0.45359237 kg, the US liquid gallon is 3.785411784 L, and mechanical horsepower is 745.7 W. Reverse pages are not copies of each other; they cover the situation where that unit is the one you already have.

US and Imperial gallons, troy ounces and nautical miles are called out on the pages that could be confused with them. Guides on centimetres, kilograms and Celsius sit beside the tools if you want the why before the widget.