Square Footage
Calculate square footage for a room, floor, or whole house from length and width measurements.
Formula
Area = Length × Width (for rectangles)
Multiply length by width for rectangles. For circles use π × r². For triangles use 0.5 × base × height. Add multiple areas together for total.
Worked Examples
Example 1: Living Room
Problem:Calculate square footage of a 20 ft × 15 ft living room.
Solution:Length = 20 feet\nWidth = 15 feet\n\nArea = Length × Width\nArea = 20 × 15 = 300 square feet\n\nFor flooring (with 10% waste):\n300 × 1.10 = 330 sq ft\n\nCarpet (square yards):\n300 ÷ 9 = 33.3 square yards
Result:300 square feet (33.3 sq yds)
Example 2: Multiple Rooms
Problem:Calculate total square footage: bedroom 12×10, bathroom 8×6, closet 4×3.
Solution:Bedroom: 12 × 10 = 120 sq ft\nBathroom: 8 × 6 = 48 sq ft\nCloset: 4 × 3 = 12 sq ft\n\nTotal = 120 + 48 + 12 = 180 square feet
Result:180 total square feet
Example 3: Circular Patio
Problem:Calculate square footage of a patio with 12-foot radius.
Solution:Radius = 12 feet\n\nArea = π × r²\nArea = 3.14159 × 12²\nArea = 3.14159 × 144\nArea = 452.4 square feet\n\nFor pavers (with 15% waste):\n452.4 × 1.15 = 520 sq ft
Result:452 square feet circular patio
Frequently Asked Questions
How do I calculate square footage?
For a rectangle, multiply length × width. Example: 12 ft × 15 ft = 180 square feet. For irregular shapes, break into rectangles and add together. For circles: π × radius². Include closets and alcoves. Exclude stairs, fireplaces, and non-livable spaces.
How many square feet in a 10×10 room?
10 feet × 10 feet = 100 square feet. This is a common small bedroom or office size. For flooring/carpet: add 5-10% for waste. For paint: calculate wall area (perimeter × height), not floor area.
What is the difference between square feet and square yards?
1 square yard = 9 square feet (3 ft × 3 ft). Carpet is sold by square yards. Flooring and most construction by square feet. To convert: Square yards = Square feet ÷ 9. Example: 180 sq ft = 20 sq yds.
How do I measure square footage of a house?
Measure exterior dimensions or each room individually. Include: All finished living spaces, closets, hallways. Exclude: Garage, unfinished basement, attic (unless finished), porches, decks. For multi-story: measure each level. Break irregular shapes into rectangles. Professional appraisers may have different standards.