Calculate square footage for any shape with unit conversions to sq ft, sq in, sq yd, sq m, and acres. Includes waste factor and materials cost estimation for flooring, painting, roofing, and construction projects.
A square footage calculator is an area measurement tool that calculates the total surface area of floors, walls, rooms, yards, or land parcels in square feet and other common units. Also known as a sq ft calculator, footage calculator, or area calculator, this tool helps homeowners, contractors, designers, and DIY enthusiasts accurately measure spaces for flooring, painting, roofing, landscaping, and construction projects.
Our free square footage calculator supports multiple geometric shapes (rectangle, square, circle, triangle), converts between different measurement units (feet, inches, yards, meters, centimeters), displays results in five different area units (square feet, square inches, square yards, square meters, acres), and includes optional features like quantity multiplication, waste factor adjustment (typically 5-15% for materials), and materials cost estimation per square unit.
Unlike simple length × width calculators, our tool handles complex shapes, automatically converts mixed units, applies industry-standard waste factors for materials like tile, hardwood, carpet, or roofing shingles, and calculates total project costs when you input material prices. The calculator outputs precise measurements in both imperial (sq ft, sq in, sq yd) and metric (sq m) units, plus acres for land measurement, making it versatile for any project from small room renovations to large property assessments.
Whether you're estimating how much tile to buy for a bathroom, calculating paint coverage for walls, determining roofing shingle quantities, measuring lawn area for sod or fertilizer, or assessing property size for real estate purposes, this calculator provides accurate square footage with waste allowance to ensure you purchase sufficient materials without significant over-ordering.
Formula: Length × Width (for rectangles) or Side × Side (for squares). Measure the longest wall for length and perpendicular wall for width. Convert all measurements to feet first.
Room: 12 ft × 15 ft
12 × 15 = 180 sq ft
+ 10% waste = 198 sq ft needed
Formula: π × Radius² (where π ≈ 3.14159). Measure from center to edge for radius, or divide diameter by 2. Perfect for round patios, pools, or gazebos.
Patio radius: 8 feet
3.14159 × 8² = 201.06 sq ft
Round pool or patio area
Formula: (Base × Height) ÷ 2. Measure the bottom edge (base) and perpendicular height from base to opposite point. Common for gabled walls or angular rooms.
Base: 10 ft, Height: 12 ft
(10 × 12) ÷ 2 = 60 sq ft
Gable wall or attic space
For multiple identical rooms, calculate one area and multiply by quantity. Always add waste factor: 5-10% for hardwood/carpet, 10-15% for tile, 10-20% for paint.
3 rooms @ 180 sq ft each = 540 sq ft
+ 10% waste = 594 sq ft
Total material needed
Calculate area for rectangles, squares, circles, and triangles. Perfect for rooms, pools, patios, gables, and irregular spaces. No need for separate calculators - one tool handles all common geometric shapes.
Input measurements in feet, inches, yards, meters, or centimeters - the calculator automatically converts to square feet and other units. Mix units freely: length in feet, width in inches - no manual conversion needed.
Add 0-100% waste factor for materials that require cutting, fitting, or allowance for damage. Industry-standard percentages: tile 10-15%, hardwood 5-10%, paint 10-20%. Ensures you buy enough without significant excess.
Enter material price per square foot, yard, or meter to instantly calculate total project cost including waste. Compare materials easily: $3/sq ft tile vs $5/sq ft hardwood for your 300 sq ft room.
See results in 5 units simultaneously: square feet (sq ft), square inches (sq in), square yards (sq yd), square meters (sq m), and acres (ac). Perfect for materials sold in different units or international projects.
Calculate multiple identical areas at once. Three bedrooms same size? Enter dimensions once, set quantity to 3, get total square footage instantly. Saves time for multi-room projects.
Scenario: Installing tile in a 12 ft × 15 ft kitchen. Tile costs $4.50 per sq ft. Need 10% waste for cuts and breakage.
Calculation: 12 × 15 = 180 sq ft. With 10% waste: 180 × 1.10 = 198 sq ft. Cost: 198 × $4.50 = $891
Result: Order 198 sq ft of tile, budget $891 for materials
Scenario: Painting a bedroom with 4 walls (10 ft × 8 ft ceiling height). Paint covers 350 sq ft per gallon. Need 15% waste for texture/absorption.
Calculation: Total wall area: (10+10+12+12) × 8 = 352 sq ft. With 15% waste: 352 × 1.15 = 404.8 sq ft. Gallons: 404.8 ÷ 350 = 1.16 → 2 gallons
Result: Buy 2 gallons of paint (allowing for 2 coats if needed)
Scenario: Roof is 40 ft × 25 ft. Shingles sold per "square" (100 sq ft). Need 10% waste for overlap and ridge caps.
Calculation: 40 × 25 = 1,000 sq ft. With 10% waste: 1,000 × 1.10 = 1,100 sq ft. Squares needed: 1,100 ÷ 100 = 11 squares
Result: Order 11 squares of roofing shingles
Scenario: Laying sod in backyard (50 ft × 30 ft). Sod comes in pallets covering 450 sq ft each. Add 5% for irregular edges.
Calculation: 50 × 30 = 1,500 sq ft. With 5% waste: 1,500 × 1.05 = 1,575 sq ft. Pallets: 1,575 ÷ 450 = 3.5 → 4 pallets
Result: Order 4 pallets of sod (1,800 sq ft total)
Scenario: Measuring lot size for property listing. Lot is 150 ft × 200 ft. Convert to acres for MLS listing.
Calculation: 150 × 200 = 30,000 sq ft. Acres: 30,000 ÷ 43,560 = 0.6887 acres ≈ 0.69 acres
Result: List property as 0.69 acres or 30,000 sq ft
Scenario: Building circular patio around pool, radius 12 feet. Pavers cost $8 per sq ft.
Calculation: π × 12² = 3.14159 × 144 = 452.39 sq ft. Cost: 452.39 × $8 = $3,619.12
Result: 452 sq ft of pavers needed, $3,619 budget
Measure the length and width of the room in feet using a tape measure. Multiply length × width to get square feet. For example: a room that is 12 feet long and 10 feet wide is 12 × 10 = 120 square feet. For irregular rooms, divide into rectangles, calculate each section, then add them together.
Waste factor accounts for material lost during cutting, fitting, breakage, and imperfect installations. Recommended percentages: tile 10-15% (complex patterns need more), hardwood/laminate 5-10%, carpet 5-10%, paint 10-20%, roofing 10-15%. Without waste factor, you'll run short and face delays waiting for additional materials.
1 square yard = 9 square feet. Since 1 yard = 3 feet, when you square both sides: (1 yd)² = (3 ft)², so 1 sq yd = 9 sq ft. Carpet is often sold by the square yard. To convert: divide square feet by 9. Example: 180 sq ft ÷ 9 = 20 square yards of carpet.
Yes! Our calculator allows you to enter length in one unit (e.g., feet) and width in another (e.g., inches), and it automatically converts to calculate accurate square footage. For example: length = 12 feet, width = 18 inches → the calculator converts 18 inches to 1.5 feet, then calculates 12 × 1.5 = 18 sq ft.
Step 1: Measure room length and width at the widest points (walls aren't always perfectly straight). Step 2: Multiply for square footage. Step 3: Add 5-15% waste factor depending on material and pattern. Step 4: For multiple rooms, calculate each separately then add together. Always round up when ordering materials.
Method 1 (Subtract): Calculate the main room area, then calculate closet/alcove areas separately and subtract. Method 2 (Add): Divide room into rectangles (main room + closet), calculate each, add together. For flooring/carpet, include closet areas. For painting, calculate walls separately - alcoves add perimeter.
One gallon of paint typically covers 350-400 square feet of smooth wall with one coat. Textured walls, porous surfaces, or dark-to-light color changes require more. Formula: (Total sq ft ÷ 350) × number of coats = gallons needed. Always add 10-20% for touchups and waste. Example: 400 sq ft wall, 2 coats → (400 ÷ 350) × 2 = 2.3 gallons → buy 3 gallons.
1 acre = 43,560 square feet. To convert sq ft to acres: divide by 43,560. Example: 10,000 sq ft ÷ 43,560 = 0.2296 acres (about ¼ acre). To convert acres to sq ft: multiply by 43,560. Example: 0.5 acres × 43,560 = 21,780 sq ft. Our calculator shows both automatically.
Always measure inside wall to inside wall (the actual floor space). Don't include wall thickness. Use a tape measure along the floor, not ceiling or mid-wall. For irregular rooms with bumps or alcoves, break into rectangles and measure each section separately.
While the calculator gives you total square footage needed, complex patterns like diagonal, herringbone, or chevron require higher waste factors (15-20% instead of 10%). The calculator's waste factor feature accommodates this. For exact tile count, divide total sq ft by individual tile area (e.g., 12" × 12" tile = 1 sq ft each).
| Square Feet (sq ft) | Square Inches (sq in) | Square Yards (sq yd) | Square Meters (sq m) | Acres |
|---|---|---|---|---|
| 1 | 144 | 0.1111 | 0.0929 | 0.000023 |
| 100 | 14,400 | 11.11 | 9.29 | 0.0023 |
| 500 | 72,000 | 55.56 | 46.45 | 0.0115 |
| 1,000 | 144,000 | 111.11 | 92.90 | 0.0230 |
| 5,000 | 720,000 | 555.56 | 464.52 | 0.1148 |
| 43,560 | 6,272,640 | 4,840 | 4,046.86 | 1.0 (1 acre) |
Always round up when ordering materials: If calculator shows 247.6 sq ft, order 248 sq ft minimum. Better to have extra than run short mid-project. Leftover flooring/tile is useful for future repairs.
Measure twice, calculate once: Double-check all measurements before ordering expensive materials. Walls aren't always straight - measure at multiple points and use the longest dimension to ensure coverage.
Account for pattern matching: Patterned materials (wood grain, tile designs, wallpaper) need extra for matching. Add 15-25% waste instead of standard 10% for complex patterns or diagonal installations.
Subtract large obstacles: For flooring, subtract built-in cabinets, islands, tubs, or large permanent fixtures. Don't subtract for appliances or furniture that can be moved. For walls, subtract large windows and doors.
Use consistent units: Don't mix feet and inches in your head - convert everything to feet (with decimals) or use calculator's mixed unit feature. 6 inches = 0.5 feet, 3 inches = 0.25 feet, 9 inches = 0.75 feet.
Consider material packaging: Materials come in specific sizes (carpet rolls, tile boxes, paint gallons). Check packaging before ordering - you might need to round up to full boxes/rolls even if calculator shows exact footage.
For multi-room projects, calculate separately: Don't assume rooms are identical - measure each individually. Variations in wall straightness, corners, and built-ins mean "identical" rooms often differ by 5-10 sq ft.
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