Area conversion, with the squaring made honest
Area is where unit conversion stops being intuitive, because every factor must be squared. A metre is 3.28084 feet, but a square metre is 3.28084² = 10.7639 square feet — and a square mile is not a million of anything tidy, it is 640 acres. This converter handles eight area units at once — square inches, feet, yards and miles, square metres and kilometres, acres and hectares — running every conversion through square metres with exact factors, and showing your area in all eight so no second conversion is ever needed. At the default, 100 square feet is 9.290304 square metres, the conversion behind every property listing that crosses the Atlantic. The pre-set pair pages, Square Feet to Square Meters and Square Meters to Square Feet, carry full tables for that one pair, and to measure a room or a plot in the first place, the Square Footage Calculator in the Construction section takes lengths and widths directly.
The units, from a stamp to a county
The set spans ten orders of magnitude and two civilisations of land measure. The metric units are decimal and transparent: a hectare is a 100 m × 100 m square (its name says so: a hundred ares, an are being 100 sq m), and a square kilometre is 100 hectares exactly. The imperial units carry history instead: the acre was the land a team of oxen could plough in a day, standardised as a strip one furlong long by one chain wide — 660 ft × 66 ft, which is why it holds the oddly precise 43,560 square feet, a number this page reproduces exactly rather than approximating. A square mile containing exactly 640 acres is the same history in surveyor's form. Neither system is wrong; they are answers to different centuries' questions, and converting between them exactly, as here, beats memorising approximations like “an acre is about 0.4 hectares” (it is 0.4047, and the 1% gap is an entire garden on a farm-sized plot).
Property, land and the listings trap
The everyday jobs are property-shaped. Homes are listed in square feet in the US and square metres almost everywhere else, so a 1,200 sq ft apartment is 111.5 sq m and a 90 sq m flat is 969 sq ft — the conversion that decides whether a listing is spacious or optimistic. Land flips the units upward: a US plot quoted in acres meets a European one in hectares, with 1 hectare = 2.47105 acres, close enough to 2.5 for a glance and far enough off to matter for a price. Gardeners and farmers dose by area — seed, feed and fertiliser rates come per acre or per hectare depending on the bag's origin — and a factor-of-2.47 error is an expensive afternoon. In every case the safe method is the one this page uses: convert to one base unit with exact factors, then out to the target, and read the whole row of units before acting, because the figure that catches an error is usually a neighbouring unit you happen to know.
Worked example
100 square feet = 9.290304 square metres. Through the base unit: 100 × 0.09290304 = 9.290304 sq m, and back again, 9.290304 ÷ 0.09290304 = 100 sq ft exactly. The benchmark to memorise: 1 acre = 43,560 square feet (and 4,046.8564224 sq m, or 0.4047 hectares) — enter 1 acre and convert to square feet to watch the converter land on it to the digit.
How to use this calculator
- Enter the area.
- Choose the unit it is in and the unit you want.
- Read the headline answer and the all-units table.
- Check the stats for the landlord-and-land set: square metres, square feet, acres and hectares side by side.
Why nobody's intuition survives squaring
The persistent human error with area is to convert it with the length factor: told that a metre is about 3.28 feet, people price a 50 sq m floor as “about 164 square feet”, when the true figure is 538. The factor between the areas is the factor between the lengths, squared — small unit differences grow teeth when squared, which is also why a room only 10% wider and 10% longer is 21% more floor, and why a 20-inch pizza (314 sq in) is not twice a 14-inch pizza (154 sq in) but a fraction over twice, a fact pizza menus have monetised for decades. The defence is mechanical: never scale an area by a length factor, and let a base-unit chain like this page's do the squaring for you. If a converted area does not look roughly (length factor)² times the original, something other than arithmetic has gone wrong.