Square Footage Calculator
Enter each room or shape in one unit - the calculator sums square footage and shows square meters beside it.
About Square Footage Calculator
Calculate square footage for flooring, paint, landscaping, or a whole floor plan without a spreadsheet. Pick rectangle, square, circle, triangle, or trapezoid, enter dimensions in feet, meters, inches, or centimeters, and add as many rooms or regions as you need. The live total shows square feet and square meters together - including common sizes like a 12×12 room (144 sq ft). Split an L-shaped space into two rectangles and add both rows. For length-only unit swaps, use CM to Inches or MM to Inches.
How to Use Square Footage Calculator
- Choose the unit you measured with (ft, m, in, or cm) - use the same unit for every shape in one run.
- Pick a shape and enter its dimensions (width × length, side, radius, base × height, or trapezoid bases + height).
- Optional: label the room, then click Add area for the next space or L-shape section.
- Read each row in sq ft / sq m and copy the combined total when you are done.
Square Footage Calculator Formula
Rectangle / square: length × width. Circle: π × radius². Triangle: 0.5 × base × height. Trapezoid: 0.5 × (base a + base b) × height. Convert: 1 sq m ≈ 10.764 sq ft; 1 sq ft ≈ 0.0929 sq m. Example: 12 × 16 ft = 192 sq ft ≈ 17.8 sq m.
Square Footage Calculator Examples
How many sq ft is a 12x12 room?
12 × 12 = 144 square feet (about 13.4 square meters).
10x12 living room
10 × 12 ft rectangle = 120 sq ft (about 11.15 sq m).
L-shaped room as two rectangles
Add 12×10 (120) and 5×4 (20) to get 140 sq ft combined - the usual contractor method for irregular plans.
Circular patio
Radius 5 ft → π × 5² ≈ 78.54 sq ft.
Trapezoid garden bed
Bases 4 m and 6 m with height 3 m → 0.5 × (4 + 6) × 3 = 15 sq m.
Common Use Cases
- Estimate flooring, carpet, or tile coverage
- Plan paint or wallpaper from wall or floor area
- Size patios, decks, lawns, and garden beds
- Break L-shaped or multi-room plans into addable shapes
- Convert DIY measurements between square feet and square meters
- Quick-check listing or contractor square-footage claims
Frequently Asked Questions about Square Footage Calculator
- How do you calculate square footage?
- For a rectangle, multiply length by width in the same unit (a 10 × 12 ft room is 120 sq ft). For irregular spaces, split into non-overlapping shapes, calculate each area, and add them - this square footage calculator does that when you add multiple rows.
- How many square feet is a 12x12 room?
- 144 square feet, about 13.4 square meters. Other common sizes: 10×10 = 100 sq ft, 12×16 = 192 sq ft, 15×15 = 225 sq ft.
- How do I measure an L-shaped room?
- Split the L into two rectangles, enter each as its own area row, and read the summed total. That is the same approach contractors and appraisers use for irregular footprints.
- Which shapes are supported?
- Rectangle, square, circle (radius), triangle (base × height / 2), and trapezoid (average of two bases × height). Add as many shapes as you need.
- Can I mix feet and meters in one total?
- Enter every shape in the same dimension unit for one calculation. The result always shows both square feet and square meters so you can compare units after the math.
- How do I calculate square footage with inches?
- Either switch the unit control to Inches and enter full inch values, or convert first (10 ft 6 in = 10.5 ft) and stay on Feet. If both sides are in inches, area in sq in ÷ 144 = sq ft.
- Does my floor plan leave the device?
- No. All area math runs in your browser. Dimensions are not uploaded.
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