Square Footage Calculator
Square feet of a rectangle, circle, triangle or L-shaped room from your measurements, converted to square yards, meters and acres, with cost per square foot.
Square Footage Calculator: with the default inputs, area is 120 ft².
Circle, triangle and the second rectangle of an L-shape are under More options.
Same-size rooms, tiles, panels, lots…
- Square yards
- 13.33
- Square meters
- 11.15
- Acres
- 0.0028
- Cost
- $0.00
Assumptions
- The L-shape assumes the two rectangles don't overlap.
- Conversions: 1 ft = 0.3048 m exactly; 1 acre = 43,560 ft².
| Price per sq ft | Total | Per m² | Roughly what that buys |
|---|---|---|---|
| $1.00 | $120.00 | $10.76 | Sod, gravel, basic mulch |
| $2.50 | $300.00 | $26.91 | Sheet vinyl, budget laminate |
| $5.00 | $600.00 | $53.82 | Mid-range LVP, carpet with pad |
| $8.00 | $960.00 | $86.11 | Engineered hardwood, porcelain tile |
| $12.00 | $1,440.00 | $129.17 | Solid hardwood, stamped concrete patio |
| $20.00 | $2,400.00 | $215.28 | Stone paving, high-end tile |
Material only — labour is usually another half to two times the material cost. The prices are illustrative brackets, not quotes; enter your own under More options and it appears as a row here.
How this is worked out
The formula
Rectangle: A = length × width Circle: A = π × (diameter ÷ 2)² Triangle: A = √(s(s − a)(s − b)(s − c)), s = (a + b + c) ÷ 2 L-shape: A = (L₁ × W₁) + (L₂ × W₂) 1 yd² = 9 ft² 1 m² = 10.764 ft² 1 acre = 43,560 ft²
Open How it’s calculated above to see this worked through with your own numbers.
What you enter
- Shape
- Circle, triangle and the second rectangle of an L-shape are under More options.Rectangle / square · L-shape (two rectangles — More options) · Circle (More options) · Triangle, three sides (More options)
- Length
- A number.in ft, in, yd, m, cm · 0 or more · defaults to 12
- Width
- A number.in ft, in, yd, m, cm · 0 or more · defaults to 10
- Number of identical areas
- Same-size rooms, tiles, panels, lots…from 1 to 10000 · whole numbers only · defaults to 1
- Second rectangle length(under More options)
- Split the L into two rectangles that don't overlap.in ft, in, yd, m, cm · 0 or more · defaults to 6
- Second rectangle width(under More options)
- A number.in ft, in, yd, m, cm · 0 or more · defaults to 4
- Diameter(under More options)
- A number.in ft, in, yd, m, cm · 0 or more · defaults to 10
- Side a(under More options)
- A number.in ft, in, yd, m, cm · 0 or more · defaults to 10
- Side b(under More options)
- A number.in ft, in, yd, m, cm · 0 or more · defaults to 12
- Side c(under More options)
- A number.in ft, in, yd, m, cm · 0 or more · defaults to 8
- Cost per square foot(under More options)
- Flooring, paint, sod, rent — anything priced per sq ft. Leave 0 to skip.in dollars · 0 or more · defaults to 0
What you get back
- Areamain answer
- Square yards
- Square meters
- Acres
- Cost
What this assumes
- The L-shape assumes the two rectangles don't overlap.
- Conversions: 1 ft = 0.3048 m exactly; 1 acre = 43,560 ft².
About this calculator
Square footage is the number behind almost every estimate — flooring, paint, drywall, sod, tile, rent, property listings. Pick the shape that matches the space, type the measurements, and the calculator returns the area in square feet along with square yards (carpet), square meters (most product data sheets) and acres (land).
How to measure a room
Measure wall to wall at floor level with a tape, in feet and inches, and convert inches to a decimal (6 in = 0.5 ft, 3 in = 0.25 ft). For a plain rectangle that's all you need. For anything else:
- L-shaped or T-shaped rooms: draw the outline, then split it into rectangles that don't overlap. Measure each one and add them — that's what the L-shape mode does. For more than two rectangles, run the calculator per section and add the results, or use Number of identical areas for repeats.
- Bay windows, alcoves and closets: treat them as their own small rectangles and add them if you're buying flooring or paint. Listings usually exclude closets under about 2 ft deep.
- Round rooms and patios: measure the widest point (diameter). The calculator uses π × radius².
- Triangular corners: measure all three sides; Heron's formula handles any triangle without needing the height.
Interior vs. exterior square footage
Real-estate "gross living area" is measured from the exterior walls and only counts finished, heated, above-grade space (garages and unfinished basements are excluded). What you measure inside a room will be roughly 5–8% less than the listing figure because of wall thickness. Use interior measurements for materials and exterior ones for appraisals.
Turning area into a purchase
Flooring and tile are sold per square foot but shipped by the box, carpet by the square yard, sod by the pallet (usually 450–500 ft²). Materials with a pattern or a lot of cuts need a waste factor on top — see the flooring and tile calculators, which do that step for you. Enter a Cost per square foot under More options to get a quick budget number.
Frequently asked questions
▸How do I calculate square footage?
Multiply length by width, both in feet. A 12 ft by 10 ft room is 120 sq ft. For odd shapes, break the space into rectangles, calculate each and add them together.
▸How many square feet are in a square yard?
Nine. A square yard is 3 ft × 3 ft. Divide square feet by 9 to get square yards — the unit carpet is usually quoted in.
▸How do I convert square feet to square meters?
Divide by 10.764. A 200 sq ft room is about 18.6 m². Going the other way, multiply square meters by 10.764.
▸How many square feet in an acre?
43,560. A quarter-acre lot is 10,890 sq ft, roughly 104 ft × 104 ft.
▸Does square footage include closets and hallways?
For buying flooring or paint, yes — include every surface you'll cover. For real-estate listings, closets and halls in finished space count, but garages, porches and unfinished basements don't.
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