QuickToolStackQuickToolStack

Length unit converter

History of length

Length has been one of the most essential and earliest units of measurement in human civilization. From ancient cubits based on the forearm to the globally standardized meter, people have always needed to measure distances — for land, construction, trade, and navigation. The metric system, with units like millimeters, centimeters, and kilometers, was officially introduced during the French Revolution, aiming to simplify conversions with its base-10 design. Meanwhile, the imperial system — using inches, feet, yards, and miles — has roots in Roman and Anglo-Saxon traditions and is still commonly used in the United States today. Accurate length conversion is crucial in everything from science and engineering to travel and everyday DIY tasks.