Square footage calculator
The hardwood you like costs $6.50 per square foot and the installer quotes by the square foot too, so before you call anyone you need the square footage of the room.
- Accurate unit conversion
- Practical examples included
- Instant results as you type
Square footage calculator
Enter your numbers and press Calculate
How to use the square footage calculator
The calculator needs just three pieces of information:
1. Length: the longer side of the space. Decimals are fine (for example 12.5). 2. Width: the side perpendicular to the length. 3. Measurements in meters?: switch it off if you measured in feet — the standard for US rooms — or leave it on for meters.
The formula is plain multiplication:
Square footage = length × width
Conversions use the exact international factors: 1 ft² = 0.09290304 m² and 1 yd² = 9 ft².
Worked example: a 12 ft by 15 ft living room, toggle off.
- Area = 12 × 15 = 180 sq ft
- In square meters: 180 × 0.09290304 = 16.72 m²
- In square yards: 180 / 9 = 20 yd²
For an L-shaped room, split it into two rectangles, run each through the calculator, and add the results. The same trick works for walls when you are estimating paint: enter the wall's length and its height instead of length and width.
Square footage examples by room
These are typical room sizes in an American single-family home. Run any of them through the calculator and compare with your own house:
| Room | Size (ft) | sq ft | m² |
|---|---|---|---|
| Bedroom | 11 × 12 | 132 | 12.26 |
| Living room | 15 × 18 | 270 | 25.08 |
| Kitchen | 10 × 12 | 120 | 11.15 |
| Two-car garage | 20 × 20 | 400 | 37.16 |
Flooring budget: for the 15 × 18 ft living room, hardwood at $6.50 per square foot comes to 270 × 6.50 = $1,755. Pros recommend adding 5-10% for cuts and waste: with 8% extra you would order about 292 sq ft (270 × 1.08 = 291.6), roughly $1,895 in material.
Carpet quirk: US carpet is often priced by the square yard. The same living room is 270 / 9 = 30 square yards, so carpet at $28 per square yard costs 30 × 28 = $840. The calculator gives you the yd² figure directly so you can compare quotes in either unit.
Square feet, square meters and square yards: who uses what
The square foot rules American real estate: listings, appraisals and rental ads quote living area in sq ft, and the median new single-family home runs around 2,000 sq ft (about 185.8 m²). Most of the rest of the world — Europe, Latin America, Asia — uses the square meter, so anyone comparing a US listing with an apartment abroad needs this conversion constantly.
The factor is not a round number because the foot was fixed in 1959 at exactly 0.3048 meters. Squaring it gives 1 ft² = 0.3048 × 0.3048 = 0.09290304 m². Two quick rules follow:
- From ft² to m²: multiply by 0.0929.
- From m² to ft²: multiply by 10.7639.
A yard is 3 feet, so a square yard equals 9 square feet. Carpet and sod are still commonly priced per square yard in the US, which is why this calculator shows yd² alongside the other two units.
One caveat when reading listings: square footage standards vary. Appraisers typically follow the ANSI Z765 standard, which measures from the exterior walls and excludes garages and unfinished basements, while some agents include finished below-grade space. Measuring room by room with this tool gives you the interior, usable figure — ideal for flooring, paint and furniture planning, and a good reality check against the number on the listing sheet.
About this calculator
Switch off the 'Measurements in meters?' toggle, measure length and width, and type both numbers in: a 12 × 15 ft living room is 180 square feet, which puts the flooring at about $1,170 before labor. The calculator also shows the result in square meters (m²) and square yards (yd²) — handy when a product sheet from Europe lists coverage per m², or when carpet is priced by the square yard, as it still often is in the US. And if you are working from a European floor plan in meters, leave the toggle on and the tool converts the other way, from m² to ft².
Frequently asked questions
How many square feet are in a square meter?
One square meter equals 10.7639 square feet (exactly 1 / 0.09290304). To go from m² to sq ft, multiply by 10.7639; to go the other way, multiply square feet by 0.0929. Example: an 80 m² European apartment is 80 × 10.7639 = 861.11 sq ft, while a 1,000 sq ft condo is about 92.9 m².
How do I calculate the square footage of an irregular or L-shaped room?
Split the room into imaginary rectangles, calculate each one with the tool, and add the results. A 16 × 12 ft L-shaped room with an 8 × 5 ft nook is 192 + 40 = 232 sq ft. For curved or very irregular areas, approximate with the smallest rectangle that encloses them and accept a small margin of error, or measure from a floor plan if you have one.
Can I use this calculator for walls and paint?
Yes. A wall's area uses the same formula: wall length × height. An 18 × 8 ft wall is 144 sq ft. Subtract doors (about 20 sq ft each) and windows (about 12-15 sq ft) to fine-tune. One gallon of paint covers roughly 350 sq ft per coat, so that wall takes about 0.41 gallons per coat, or 0.82 gallons for two coats.
Why doesn't my room-by-room total match the listed square footage?
Because listing square footage usually follows exterior measurements. Under the common ANSI Z765 approach, area is measured from the outside walls, so wall thickness counts, while garages and unfinished basements are excluded. Measuring room by room gives interior usable space, typically 5-15% less than the listed figure. Neither number is wrong; they measure different things.