There are 0.404685642 hectare in an acre. To find out how many hectares there are in "x" acres, multiply the number of acres "x" by 0.404685642.
1 Acre = 0.404685642 Hectares
There are 0.404685642 hectares in an acre, because an acre is defined as the area of 1 chain (66 ft) by 1 furlong (660 ft), that makes 66 ft * 660 ft = 43 560 sq. feet (or 4046.8564 sq. meters). Hectare is defined as the area of 100 ares (1 are is 100 sq. meters), and equals to 100 * 100 = 10 000 sq. meters, that makes 4046.8564 / 10000 = 0.404685642 hectares in an acre.
For example, to find out how many hectares there are in an acre and a half, multiply the acre value by the conversion factor, that makes 1.5 acres * 0.404685642 = 0.6 hectares in an acre and a half.
Acre is an imperial and US Customary area unit and defined as an area of 1 chain by 1 furlong (66 feet * 660 feet). 1 acre equals to 43560 square feet, 4840 sq. yards or 4046.85 sq. meters and about 40 percent of a hectare. The abbreviation is "ac".
Hectare is a metric system area unit and defined as 100 ares (hectare comes from "hecto" + "are", means 100 ares). 1 are is 100 square meters, that makes 1 hectare equals to 10 000 square meters. The abbreviation is "ha".