Convert Square Perch (perch²) to Acre (US Survey) (ac (US)) instantly.
About these units
Square Perch (perch²)
A square perch is equivalent to a square rod, as "perch" was another historical name for a rod, used in various medieval and regional English measurement systems. Perches commonly appeared in church records, tithing assessments, and agricultural inventories. Because the perch was both a length and an area unit, it played dual roles in land taxation and construction. These overlapping terminologies—rod, pole, perch—reflect the organic evolution of measurement in medieval Europe, long before unified systems took hold.
Acre (US Survey) (ac (US))
The US survey acre is based on the US survey foot, making it slightly different from the international acre. With a value of 43,560 survey-square feet, it appears extensively in historical property records and federal land surveys. Because millions of acres in the United States were mapped using PLSS, the survey acre remains necessary for interpreting legal land rights, even though modern mapping often uses metric units or the international foot. This specialized acre illustrates how subtle unit differences can survive for centuries due to legal and administrative inertia.