The most common abbreviation for “per square foot” is SF, sq ft, or ft². In real estate and construction, you will often see “$/SF” or “PSF” to mean “per square foot,” while “sq ft” is the standard written abbreviation in most other contexts.
Formula
The area in square feet is found by multiplying the length (in feet) by the width (in feet):
Area (sq ft) = Length (ft) × Width (ft)
For a square or rectangle, that’s all there is to it. If you have a circle, the formula is Ï€ × radius² (where radius is in feet). If you have a triangle, it’s ½ × base × height (both in feet). The result is always in square feet when all input dimensions are in feet.
Worked Example
Using the calculator’s default values: a room that is 40 feet long and 25 feet wide.
- Write down the length: 40 ft
- Write down the width: 25 ft
- Multiply: 40 × 25 = 1000
- The area is 1,000 square feet.
In metric, that same room is about 12.19 m × 7.62 m = 92.9 m². The calculator shows the metric equivalent as 92.90 m², which matches.
Why There Are So Many Abbreviations
Different industries standardized on different abbreviations before the internet made everything global. In the US real estate industry, “SF” is the norm in listings and commercial leases. In architectural drawings, you’ll see “SQ. FT.” or just “FT²”. In engineering and scientific writing, the symbol “ft²” is preferred because it’s unambiguous. In construction contracts, “PSF” (pounds per square foot) is common when talking about loads, and “$/SF” is common for pricing. All of these mean the same thing in context, but the abbreviation you choose signals which field you’re in.
How to Read “Per Square Foot” Pricing
When a commercial lease says “$25/SF”, it usually means $25 per square foot per year, not per month. So a 2,000 sq ft office at $25/SF/year costs $50,000 per year, or about $4,167 per month. Residential rent is typically quoted per month, so “$2/SF” in a residential ad means $2 per square foot per month. Always check whether the rate is annual or monthly.
For construction materials, “per square foot” is straightforward: if tile costs $3/sq ft, a 200 sq ft floor costs $600. But some products are sold by the square yard (9 sq ft), so be careful when comparing prices.
Common Mistakes and Misconceptions
- Confusing ft² with ft³: Square feet is area (2D), cubic feet is volume (3D). A 10 ft × 10 ft floor is 100 sq ft; if you also have 8 ft ceilings, the room volume is 800 cubic feet.
- Mixing units: Always convert inches to feet before multiplying. 12 inches = 1 foot, so a 6-inch tile is 0.5 ft.
- Using the wrong abbreviation in a contract: Write out “square feet” at least once, then use “sq ft” or “SF” consistently.
- Assuming all “per square foot” prices are the same basis: Some prices are for material only, some include installation, some are for per year, some per month.
When You Need More Than Square Feet
Square footage is only the starting point for many projects. For example, to buy carpet, you need square yards (divide sq ft by 9). To pour concrete, you need cubic yards (multiply area by thickness in feet, then divide by 27). To paint a room, you need the wall area, not the floor area. For sod or grass seed, you need the area in square feet, but the product coverage varies by supplier, so always check the label.
Our calculator above gives you the pure area first, which is what you need for most comparisons. If you’re planning a project, use that number as your base and then apply the specific product’s coverage rate.
How to Choose the Right Abbreviation for Your Document
If you’re writing for a general audience, use “sq ft” — it’s the most recognized. If you’re writing for a real estate audience, “SF” is standard. If you’re writing a scientific paper, use “ft²” (with the superscript). If you’re writing a contract, spell out “square feet” on first use and then abbreviate. Consistency matters more than which one you pick.
Frequently Asked Questions
What does PSF stand for?
PSF stands for “per square foot” in construction and engineering. It’s most often used for loads, like “50 PSF” meaning 50 pounds per square foot. In real estate, you might see it as “$/PSF” meaning price per square foot.
Is “SF” the same as “sq ft”?
Yes, both mean square foot or square feet. “SF” is common in real estate and construction, “sq ft” is more common in general writing. They are interchangeable.
How do I type the square foot symbol?
On Windows, hold Alt and type 0178 on the numeric keypad to get ². On Mac, press Option + 2. In most word processors, you can also type “ft2” and then format the 2 as superscript.
Is “sqft” one word acceptable?
Yes, especially in informal writing or web searches. It’s not standard in formal documents, but it’s widely understood and often used in URLs and hashtags.
Does “per square foot” always mean area?
Yes, per square foot always refers to an amount divided by an area. But be careful: in some contexts, “square foot” might mean a board foot (lumber) or a square (roofing, where 1 square = 100 sq ft). Always confirm the unit in the specific industry.