Several units of measurements are used in Puerto Rico. The units of measure in use in Puerto Rico are based on the United States customary units. One notable exception are public roadway distances: whereas speed limits are posted in the United States customary units (miles per hour), distances are shown in the metric system (meters and kilometers) .
Several units were used before the US takeover in 1898. These units were older Spanish units.
Several units were used to measure area. Among them were the cuerda and the caballería.
In Puerto Rico, a cuerda is a traditional unit of land area nearly equivalent to 3,930 square meters, or 4,700 square yards, 0.971 acre, or 0.393 hectare (ha). The precise conversion is 1 cuerda = 3,930.395625 m2. The term "Spanish acre" instead has been used sometimes by mainlanders. A cuerda and an acre have often been treated as equal because they are nearly the same size. It continues to be an official unit of land measure in Puerto Rico today (2019).
Main article: Caballería
This was a unit of land measurement in the Spanish Viceroyalties in the Americas during the times of the Spanish Empire in the 16th through 19th centuries Puerto Rico. Widely use then, it was equivalent to 78.58 hectares (194.2 acres). This unit of measure is now (2019) obsolete.