The factor is squared, and that is the whole trap
A foot is 0.3048 metres, so people reach for that number when converting area. It gives an answer roughly three times too large, because area scales with the square of length. The correct factor is 0.3048 squared, about 0.0929 — and going the other way, one square metre is 10.764 square feet rather than 3.28.
The intuition worth carrying: doubling a room's dimensions quadruples its floor area. A 10 by 10 room is 100 sq ft; a 20 by 20 room is 400, not 200. The same relationship makes the area conversion factor the square of the length one.
Room and property sizes worth knowing
A single bedroom of about 10 by 12 feet is 120 sq ft or 11.1 m². A generous double at 14 by 16 is 224 sq ft or 20.8 m². A typical American single-family home at 2,000 sq ft is 186 m², while a typical new-build British house at around 76 m² is 818 sq ft — a genuinely large difference that the units alone can obscure.
Apartment listings show the split clearly. A "700 square foot" American apartment is 65 m², which a European listing would describe as a comfortable one-bedroom. Comparing property across the two systems without converting produces badly wrong impressions in both directions.
What counts as floor area varies more than the units do
A caution that matters more than the arithmetic: different countries and different listing standards measure floor area differently. Some include external wall thickness, some measure to the internal face. Some include balconies, garages, basements or loft space, and some exclude any area under a certain ceiling height.
The consequence is that two identical buildings can be advertised with meaningfully different areas depending on the convention used, and a precise conversion of an imprecise figure gains you nothing. When comparing properties, the measurement basis is worth establishing before the units are.
Materials, and why you should over-order
Flooring, tiling, paint and turf are all sold by area, and the conversion above tells you how much surface you have. It does not tell you how much to buy. Cutting waste, pattern matching and breakage mean the standard trade advice is to add 10% for straightforward rectangular rooms and 15% or more for diagonal layouts, patterned tile or awkward shapes.
Paint is quoted by coverage per litre or per gallon, and those figures assume a smooth sealed surface. Bare plaster, render or textured walls absorb considerably more. For larger land areas, the acres to hectares converter handles the units used above roughly a quarter-acre.
Frequently asked questions
Why can I not use 0.3048 to convert square feet?
Because area scales with the square of length. The correct factor is 0.3048 squared, or 0.09290304. Using the linear factor gives an answer roughly three times too large.
How many square feet is 100 square metres?
1,076.39 square feet. One square metre is 10.764 square feet, not 3.28.
How much extra flooring should I order?
Trade practice is about 10% over the measured area for simple rectangular rooms and 15% or more for diagonal layouts, patterned tile or awkward shapes, to allow for cutting waste and breakage.