How accurately did Indus civilization builders use measurement units?

The builders of the Indus civilization demonstrated a high degree of precision in their use of measurement units, which were effectively applied in their architectural projects.12

Archaeological excavations have uncovered several physical scales, including a decimal scale of 1.32 inches (3.35 cm) that likely extended to 13.2 inches (33.5 cm), corresponding to a "foot" unit common in western Asia. Additionally, researchers found a bronze rod marked in increments of 0.367 inches (0.93 cm), representing half a digit of a 20.7-inch (52.6 cm) "cubit," a standard also utilized in Egypt and western Asia.12

The accuracy of their construction is further supported by the discovery of objects believed to be optical squares, which surveyors likely used to offset right angles. This technical proficiency is evident in the layout of major cities like Mohenjo-daro and Harappa, which were organized according to a systematic grid pattern. While the exact complexity of their weights and measures system remains a subject of ongoing study, the practical application of these units in their structures confirms a sophisticated level of measurement accuracy.123