Area Converter

Area is length squared, so its factors are the squared length factors: a foot is 0.3048 m, but a square foot is 0.09290304 m². That is why one square metre is about 10.76 square feet and not 3.28. Pick your two units and the value passes through square metres.

Ten units, all routed through the square metre. Each unit carries a single number — the square metres it is worth — and a conversion is a multiplication by the source factor and a division by the target one. Holding one factor per unit rather than a rate for every pair is what keeps the hectares-to-acres answer consistent with the acres-to-square-metres answer; a stored grid of every pair would be a grid of chances to disagree with itself. The factors themselves are the squared length factors, and that is where intuition usually fails. A foot is 0.3048 m, but a square foot is 0.3048² = 0.09290304 m², so a square metre is 10.763910417 square feet, not 3.28. The same squaring runs through the family: a yard is three feet, so a square yard is nine square feet; a foot is twelve inches, so a square foot is 144 square inches. Because the inch has been exactly 25.4 mm since the 1959 agreement, each of these is an exact definition and the only rounding is the six decimals shown. One unit needs naming out loud. The acre here is the international one, 4840 square yards, which works out at exactly 4046.8564224 m² — about 0.404686 hectares. The US survey acre is a different figure, 4046.873 m², and older American land records may be written in it.