How this instrument works
A square foot has no definition of its own; it is simply a foot of length, squared. Since the 1959 international yard and pound agreement fixed the foot at exactly 0.3048 metres — chosen to keep the metric inch a tidy 25.4 mm — squaring that figure gives 0.09290304 square metres exactly, with every digit terminating because 0.3048 itself is a clean decimal fraction with no repeating remainder.
American residential real estate runs almost entirely on square feet: listings, floor plans, appraisal reports and mortgage paperwork all quote living area that way, and the habit extends to construction materials too — flooring, drywall sheets, roofing shingles and paint coverage are all priced or rated per square foot. Once that figure needs to travel abroad, to an international buyer, a European contractor or a manufacturer's metric spec sheet, this exact factor is what does the translating.
One historical wrinkle briefly complicated matters. American land surveying once relied on a slightly different 'US survey foot,' defined as 1200/3937 metres rather than the international 0.3048, which made survey-based square footage a few parts per million larger than this page's figure. NIST and NOAA formally retired the survey foot at the end of 2022, so current American measurements — real estate included — rely on the same 0.3048 metre foot used everywhere else.
- Enter the area into Square feet (ft2); the field opens at 500, roughly a small studio apartment.
- Read the metric equivalent from Square metres (m2) beneath it, recalculated on every keystroke to eight decimals.
- Have dimensions instead of a total? Multiply length by width in feet first, then enter that product.
- Working the other direction? Multiply your square-metre figure by 10.7639104167 to return to square feet.
Worked example — a 500 sq ft studio apartment
An American listing advertises a studio apartment at 500 sq ft, and a prospective tenant relocating from Barcelona wants to know what that means in the square metres every European floor plan she has seen is measured in. Enter 500 into Square feet (ft2) and Square metres (m2) reads 46.45152 — a compact but workable one-room flat by continental standards, close to what many European studios actually offer.
The check by hand is simple multiplication: 500 × 0.09290304 = 46.45152, with nothing rounded away at any step. A larger 1,200 sq ft two-bedroom apartment converts to exactly 111.483648 square metres, and the same 0.09290304 factor applies identically whether the area in question is an apartment, a warehouse floor, or a single sheet of drywall rated at 32 sq ft per panel.
Questions
Is 0.09290304 square metres per square foot exact?
Yes, exactly, with no rounding anywhere in its derivation. The foot has been defined as precisely 0.3048 metres since the 1959 international yard and pound agreement, and squaring an exact decimal fraction produces another exact decimal fraction — 0.3048 × 0.3048 = 0.09290304, terminating cleanly rather than repeating. Every digit this converter returns is therefore correct to the precision it displays, not an approximation.
Why can't I just multiply by 0.3048 for an area conversion?
Because area scales as length squared, not length. Multiplying a square-foot figure by the plain length factor of 0.3048 gives an answer roughly eleven times too small — 500 ft2 would wrongly become 152.4 rather than the correct 46.45152 m2. The length factor must be applied twice for an area, which is exactly what squaring it into 0.09290304 accomplishes in a single step.
Does US land surveying use a different square foot?
It once did. American surveys historically relied on the 'US survey foot,' defined as 1200/3937 metres, a few parts per million longer than the international foot this page uses. Squared into an area, that tiny length gap widens slightly further, though it stays negligible for ordinary building measurements. NIST and NOAA officially retired the survey foot at the end of 2022, so current surveying, like everything else, now uses the same 0.3048 metre international foot.
How many square feet are in an acre or a hectare?
An acre comes to exactly 43,560 square feet by its traditional definition, which converts to 4046.8564224 square metres. A hectare, 10,000 square metres, works out to roughly 107,639.1 square feet — about 2.471 acres. Both remain common reference points: acres in American deeds and listings, hectares in most of the rest of the world's land records and farm subsidy paperwork.
Why do American and European floor-area figures for the 'same' apartment sometimes disagree?
Because the conversion arithmetic is exact but the underlying floor-area definition often isn't consistent. US listings typically follow ANSI Z765 measurement standards, measuring to the exterior face of exterior walls, while European countries apply their own national or RICS-aligned standards that may include or exclude balconies, stairwells and internal wall thickness differently. Converting a number is reliable; confirming what that number actually includes takes an extra question to the listing agent.
How much material do I need if a room measures a given number of square feet?
Convert the room's square footage to square metres first if your material is priced per square metre — tile, laminate flooring and turf commonly are outside the US — then add a waste allowance, typically 5 to 10%, to cover cutting losses and pattern matching. A 200 sq ft room, 18.580608 m2, would reasonably need around 19.5 to 20.5 m2 of material ordered to avoid running short mid-job.