Land Area Converter

What this calculation does not cover

• Every entry is turned into acres first and the other three units are derived from that acre figure, so a hectares-to-square-metres reading travels through the acre factor rather than through the 10,000 m² that defines a hectare.
• The hectare factor is stored as 0.404685642 while the square-foot and square-metre factors are stored in full, so a hectare value sent through the page and back returns about six parts in ten billion off what was typed — nothing on a parcel, but the two routes do not agree digit for digit.
• Only acres, hectares, square feet and square metres are offered; a deed, title plan or overseas listing quoting square yards, square miles, roods or perches has to be converted before its number can be entered here.
• The value box is capped at 100,000 whichever unit is selected, so the ceiling is a number rather than an area — 100,000 acres in one setting and 100,000 square feet, about 2.3 acres, in another — and anything typed above it is pulled back to the cap when the field loses focus.
• Nothing in the arithmetic separates a plan area from the ground surface beneath it, so a figure taken off a sloping site converts unit for unit while the real surface remains larger than all four numbers shown.
• The headline answer is the acre figure whichever direction you are working in, with hectares, square feet and square metres carried on the breakdown rows below it, so a metric reader takes their result off a row rather than off the result line.