How to Calculate Square Feet
To calculate square feet, multiply the length by the width when both measurements are in feet. This basic formula works for a rectangle or square room, floor, deck, patio, garage, rug area, or lawn section.
Example: A room that is 12 feet long and 10 feet wide is 12 × 10 = 120 square feet.
Square Feet Formula
- Rectangle: length × width
- Square: side × side
- Triangle: base × height ÷ 2
- Circle: π × radius²
- Wall area: wall width × wall height × number of walls
- Flooring with waste: room area × (1 + waste percentage ÷ 100)
How to Calculate Square Footage for a Room
For a room square footage calculator result, measure the longest length and widest width of the room. Use a tape measure and write the measurements in feet. If you measure inches, convert inches to feet by dividing by 12. Then multiply length by width. For irregular rooms, divide the room into smaller rectangles, calculate each part, and add the results together.
How to Calculate Square Feet for Flooring
A flooring calculator square feet estimate should include extra material for waste. Use 5% for simple rooms, 10% for most flooring projects, and 15% or more for diagonal patterns, closets, stairs, hallways, or irregular room shapes. This helps prevent running short when cutting planks, tile, vinyl, laminate, hardwood, or carpet.
How to Calculate Wall Square Footage
For a wall square footage calculator, multiply wall width by wall height. For multiple walls, calculate each wall and add the totals. Subtract doors and windows if you want net paintable or wallpaper area. This method is useful for paint, wallpaper, drywall, paneling, shiplap, and accent wall projects.
How to Calculate Square Feet for Paint
A paint square footage calculator starts with wall area, subtracts doors and windows, and multiplies by the number of coats. Many interior paints cover about 250 to 400 square feet per gallon, but textured walls, dark color changes, unfinished drywall, and primer needs may change the final amount.
How to Calculate Square Feet for Tile
A tile square footage calculator uses the project area and tile size. Tile area is tile width × tile height. Because tile projects include cuts, grout spacing, broken pieces, and pattern matching, add a waste percentage before buying.
How to Calculate Square Feet for Carpet
A carpet square footage calculator should show both square feet and square yards because carpet may be priced by either unit in the United States. To convert square feet to square yards, divide by 9.
Where This Square Foot Calculator Can Help
This area calculator can help when buying flooring, estimating paint, planning tile, measuring carpet, estimating lawn sod, comparing apartment sizes, planning home improvement projects, creating contractor estimates, and measuring patios, decks, basements, sheds, garages, and yards.
Tips Before Buying Flooring, Paint, Tile, Carpet, or Sod
- Measure twice before ordering materials.
- Add a waste percentage for cuts, mistakes, closets, stairs, and future repairs.
- Check whether the product is sold by square foot, square yard, box, gallon, roll, tile, pallet, or bag.
- Round up when buying boxes, gallons, tiles, carpet, sod, or seed bags.
- For large projects, ask your contractor to confirm measurements before purchase.
