how many square feet is one acre of land
Acre The acre is a unit of land area used in the imperial and US customary systems. It is defined as the area of 1 chain by 1 furlong (66 by 660 feet), which is exactly equal to ​1⁄640 of a square mile, 43,560 square feet, approximately 4,047 m2, or about 40% of a hectare.
Hectare The hectare (/ˈhɛktɛər, -tɑːr/; SI symbol: ha) is an SI accepted metric system unit of area equal to 100 ares (10,000 m2) or 1 square hectometre (hm2) and primarily used in the measurement of land as a metric replacement for the imperial acre.[1] An acre is about 0.405 hectare and one hectare contains about 2.47 acres.