Square Footage Calculator
Area = length × width
How Square Footage Calculations Work
Square footage measures the area of a flat surface in square feet (ft²). For any rectangle, the formula is: area = length × width. A 12 ft × 12 ft patio covers 12 × 12 = 144 sq ft. Multiplying length and width gives the total surface area you need for flooring, paint coverage, tile orders, mulch depth calculations, and material estimates across home improvement projects.
To convert square feet to square meters, multiply by 0.092903 (or divide square meters by 10.7639 to go the other way). The 144 sq ft patio equals roughly 13.38 m². For larger parcels, divide square feet by 43,560 to find acres — useful when comparing lot sizes or planning landscaping budgets.
Irregular rooms are often broken into rectangles. An L-shaped living room might be a 15 × 12 ft main section plus a 6 × 8 ft alcove: (15 × 12) + (6 × 8) = 180 + 48 = 228 sq ft total. Measure in feet and inches, convert inches to decimal feet (6 inches = 0.5 ft), then multiply. Round up slightly when ordering materials to account for waste and cuts.
Square footage is the foundation for nearly every construction calculator on this site. Once you know your area, you can estimate concrete volume (area × depth), paint gallons (area ÷ coverage rate), tile count, carpet rolls, gravel cubic yards, and more. Always measure the longest points wall to wall rather than guessing from floor plans when precision matters.
| Room Size | Square Feet | Square Meters |
|---|---|---|
| 10 ft × 10 ft | 100 sq ft | 9.29 m² |
| 12 ft × 12 ft | 144 sq ft | 13.38 m² |
| 15 ft × 20 ft | 300 sq ft | 27.87 m² |
| 20 ft × 25 ft | 500 sq ft | 46.45 m² |
Whether you are sizing a backyard patio, planning hardwood flooring, or quoting a tile job, accurate square footage prevents costly over-ordering or mid-project shortages. Enter your length and width to get instant results in square feet, square meters, and acres.
Examples
| Example | Result |
|---|---|
| 12 ft × 12 ft patio | 144 sq ft (13.38 m²) |
| 10 ft × 15 ft bedroom | 150 sq ft (13.94 m²) |
| 20 ft × 25 ft garage | 500 sq ft (46.45 m²) |
| 8 ft × 10 ft bathroom | 80 sq ft (7.43 m²) |
| 14 ft × 16 ft kitchen | 224 sq ft (20.81 m²) |
| 30 ft × 40 ft yard section | 1,200 sq ft (0.03 acres) |
| 5 m × 4 m room (metric input) | 215.28 sq ft (20 m²) |
Frequently asked questions
Multiply the room's length by its width in feet. A 12 ft × 14 ft bedroom is 168 sq ft. For metric measurements, convert to feet first or use the square meter output.
One acre equals 43,560 square feet. Divide your total square footage by 43,560 to convert to acres.
Yes. Most flooring, tile, and carpet projects add 10% waste. Measure carefully, then use the area in our concrete, paint, or flooring calculators for material quantities.