Convert Inch (in) to Inch (US Survey) (in (US)) 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.
Inch (US Survey) (in (US))
The US Survey Inch is derived from the US survey foot, making it exactly 1/12 of the US survey foot (~2.540006 cm). It is used in precise surveying applications where small differences can accumulate over large distances. Historically, it ensured consistency in cadastral maps, railroad engineering, and construction projects, especially when reconciling legacy measurements with modern geodetic data. Though seldom used outside surveying, the US survey inch highlights the need for consistency and precision in civil engineering and mapping applications.