Convert Inch (in) to Ken (ken) instantly.
About these units
Inch (in)
An inch is defined as exactly 25.4 millimeters, a precise metric-based definition that preserves its usefulness within imperial systems. Historically, the inch was based on the width of three barleycorns placed end-to-end, a charming relic of medieval measurement practices. Today, the inch is vital in manufacturing, woodworking, consumer electronics (e.g., screen sizes), and tooling standards across the US and partially in the UK. Its size is small enough to offer usable precision yet large enough to avoid unwieldy fractions for many everyday objects. Even in predominantly metric industries, certain products—such as plumbing parts, bicycle rims, and camera mounts—retain inch-based standards for compatibility. This persistence shows how technological ecosystems can outlive their measurement origins.
Ken (ken)
The ken is a traditional Japanese unit of length, typically about 1.8 meters, though historically it ranged from 1.6 to 1.9 meters depending on the era and region. The ken is deeply tied to traditional Japanese architecture, especially temple and shrine construction. In classic building design, the ken measured the spacing between pillars in wooden structures. Because Japanese architecture emphasizes modularity and harmonious proportions, the ken allowed builders to create spaces that were both structurally efficient and aesthetically consistent. Many tatami room layouts are also derived from ken-based proportions. Beyond architecture, the ken carried symbolic importance in religious and cultural contexts. Temples were often laid out using ken multiples, reinforcing a sense of order, symmetry, and sacred geometry. Even though modern Japan uses the metric system, the ken persists in the restoration and preservation of historical buildings.