Unit converters

Metric and imperial converters for everyday and professional use: length, weight, temperature, volume, speed, and land area — each tool converts both directions instantly. Handy for recipes, shipping labels, science homework, and international travel. Uses standard conversion factors; precision rounding may differ slightly from regulatory or engineering tables.

Most of these relationships are exact by definition rather than measured: an inch is defined as precisely 2.54 centimetres, and a mile as 1,609.344 metres, so any difference you see against another source is rounding rather than disagreement. A few conversions need more care. Temperature is not a simple ratio, because the Celsius and Fahrenheit scales have different zero points, which is why you cannot convert a temperature difference the same way you convert a temperature. Volume is the classic trap for recipes and fuel economy: a US gallon is about 3.785 litres while an imperial gallon is about 4.546, a difference of roughly 20 percent, and US and imperial fluid ounces differ too. When a figure matters — a dosage, a shipping declaration, a specification — match the unit on your source document rather than assuming.