Square Footage Calculator – How to Calculate Square Footage of Any Room or House
Calculate square footage of rectangles, L-shaped rooms, triangles, circles, and trapezoids. Use the multi-room builder to calculate the total square footage of an entire house. Includes cost estimator for flooring, paint, and tile.
Rectangle/Room: Length (ft) × Width (ft) = Square Feet | Triangle: (Base × Height) ÷ 2 | Circle: π × radius² | L-shaped: Split into 2 rectangles, calculate each, add together
Example: 14 ft × 12 ft room = 168 square feet
Select the shape of your room or area:
Calculate total square footage of an entire house. Add each room separately. Perfect for how to calculate square footage of a house.
Use a tape measure. Measure the longest wall from corner to corner in feet and inches. Write it down as a decimal: 12 feet 6 inches = 12.5 ft.
Measure the adjacent wall perpendicular to your first measurement. Convert inches the same way.
Length × Width = Square Footage. Example: 14 ft × 12 ft = 168 sq ft.
Calculate each room separately, then add all rooms together. Include bedrooms, bathrooms, kitchen, living room, dining room, hallways, and closets.
For flooring, tile, or carpet — add 5–10% extra for cuts, waste, and mistakes. For tile or diagonal patterns, add 15%.
Use for: Most rooms, yards, walls
Use for: Open-plan rooms, kitchens
Use for: Attic corners, bay windows
Use for: Round rooms, pools, planters
Use for: Angled walls, odd lots
| 1 Square Foot equals | Value | 1 Square Foot equals | Value |
|---|---|---|---|
| 144 square inches | 144 in² | 0.0929 square meters | 0.0929 m² |
| 0.1111 square yards | 0.111 yd² | 929.03 square centimeters | 929 cm² |
| 0.000023 acres | 0.000023 ac | 0.000093 square kilometers | 0.000093 km² |
💡 Tip — convert inches to decimal feet: Divide inches by 12. Example: 6 in = 0.5 ft, 9 in = 0.75 ft, 3 in = 0.25 ft.
What rooms to include
Include all finished, heated living areas: bedrooms, bathrooms, kitchen, living room, dining room, hallways, closets, and finished basement areas. Use our multi-room calculator above to add each room individually.
What to exclude
Exclude: garages (attached or detached), unfinished basements, open porches, patios, carports, and attic spaces that cannot be used as living area. Real estate listings follow the ANSI Z765 standard for measuring gross living area (GLA).
How to figure out square footage of an irregular house
Sketch a rough floor plan. Break the outline into rectangles. Measure each rectangle's length and width. Add the areas together for the total square footage. For L-shaped, T-shaped, or U-shaped homes — each wing is measured as a separate rectangle.
How to determine square footage for flooring
Measure each room, add up the total, then add 5–10% waste factor. For tile installations, add 10–15% because diagonal cuts waste more material. Multiply total square footage by price per square foot for total project cost. Use our cost estimator above for a quick estimate.
Multiply length (feet) × width (feet). Example: a 14 ft × 12 ft room = 168 sq ft. For other shapes, use: triangle = (base × height) ÷ 2; circle = π × radius²; L-shape = split into two rectangles and add them.
Measure the room's length and width in feet. Multiply them together. For rooms measured in feet and inches, convert inches to decimal feet first (divide inches by 12). Example: 12 ft 6 in = 12.5 ft.
Measure each room separately (length × width). Add all rooms together. Include bedrooms, bathrooms, kitchen, living areas, hallways, and closets. Exclude garage, unfinished basement, and open porches.
Divide the L-shape into two rectangles. Measure each rectangle's length and width. Calculate each area (length × width), then add both together. Example: 10×8 ft + 6×5 ft = 80 + 30 = 110 sq ft.
Measure each room, sum all areas, then add 5–10% waste overage. Multiply total sq ft by price per square foot for your material cost estimate.
Convert inches to decimal feet: divide by 12. Then multiply. Example: 12 ft 6 in × 10 ft 3 in = 12.5 ft × 10.25 ft = 128.125 sq ft.
Circle square footage = π × radius². Measure the diameter (full width), divide by 2 for radius, then: 3.14159 × radius × radius. Example: 12 ft diameter → radius 6 ft → 3.14159 × 36 = 113.1 sq ft.
Triangle area = (Base × Height) ÷ 2. The height must be perpendicular to the base. Example: base 10 ft, height 8 ft → (10 × 8) ÷ 2 = 40 sq ft.