Area converter

Nine units of area at once. The one worth memorising is that a hectare is 10,000 square metres and roughly 2.47 acres — the two units most land is described in.

Area factors are the square of the length factors, which is why the numbers look unfamiliar even when the length conversion is one you know well. A foot is 0.3048 metres, so a square foot is 0.3048² — about 0.0929 square metres, not 0.3048. That squaring is also why a room twice as long in each direction has four times the floor. The acre is the historical oddity: originally the area a yoke of oxen could plough in a day, it settled at 4,840 square yards, which is why it has no round relationship to anything metric.