Square Footage Calculator
A 12×14 ft room is 168 sq ft. With 10% waste factor for flooring, buy for 185 sq ft. At $3-8/sqft for materials, budget $500-1,480.
Square Footage Calculator
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How to Calculate Square Footage
The basic formula is Area = Length × Width for rectangular spaces. For other shapes:
| Shape | Formula | Example |
|---|---|---|
| Rectangle | L × W | 12 ft × 14 ft = 168 sq ft |
| Circle | π × r² | 10 ft diameter = 78.5 sq ft |
| Triangle | (base × height) / 2 | 8 ft × 6 ft / 2 = 24 sq ft |
| Trapezoid | ((a + b) / 2) × h | ((10+14)/2) × 8 = 96 sq ft |
| L-Shape | (L1 × W1) + (L2 × W2) | Split into 2 rectangles, add |
Unit Conversions:
- 1 sq ft = 144 sq inches
- 1 sq yard = 9 sq ft
- 1 sq meter = 10.764 sq ft
- 1 acre = 43,560 sq ft
| Material | Waste Factor | Why |
|---|---|---|
| Hardwood flooring | 10% | Cuts, defects, starter rows |
| Tile (straight lay) | 10% | Cuts at walls |
| Tile (diagonal lay) | 15% | More cuts, more waste |
| Carpet | 10-15% | Seams, room shape |
| Paint | 0% (use paint calc) | Measured differently |
| Wallpaper | 15-20% | Pattern matching |
Common Mistakes:
- Measuring in inches but entering as feet — double-check your units
- Forgetting closets, alcoves, or bay windows when measuring rooms
- Not subtracting areas you won't cover (fireplaces, islands, built-ins)
- Confusing square feet with linear feet — baseboards and trim use linear feet
Frequently Asked Questions
How do I calculate square footage of a room?
Measure the length and width of the room in feet using a tape measure. Multiply length × width. A 12×14 ft room is 168 square feet. For L-shaped rooms, divide into two rectangles, calculate each, and add them together.
How many square feet is a 12x12 room?
A 12×12 room is 144 square feet. That's exactly 16 square yards, which is useful when buying carpet (often sold by the square yard).
How do I convert square feet to square yards?
Divide square feet by 9. For example, 168 sq ft ÷ 9 = 18.67 sq yards. This conversion is essential for carpet shopping, as carpet is typically priced per square yard.
How do I measure square footage of an irregular room?
Break the room into simple shapes — rectangles, triangles, or half-circles. Calculate each section separately and add the areas together. For an L-shaped room, split it into two rectangles at the corner where the shape changes.
Do I include closets in square footage?
For flooring and paint projects, include closets if you're finishing them. For real estate listing purposes (livable square footage), closets are included but garages, unfinished basements, and attics are not. Always clarify the purpose before measuring.
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