Square Footage Calculator
Calculate area for flooring, landscaping, or renovations.
Understanding Square Footage Calculations
Whether you are ordering new hardwood flooring, planning a backyard patio, or painting a room, knowing how to accurately calculate square footage is essential. Square footage is a measurement of area, representing the size of a two-dimensional surface.
How to Calculate Square Feet Manually
The basic formula for a rectangular or square area is straightforward:
Length (ft) × Width (ft) = Square Footage (sq. ft.)
However, real-world measurements often include inches. To get the most accurate result, convert your inches into decimal feet by dividing the number of inches by 12. For example, if a room is 10 feet 6 inches long, you calculate 6 ÷ 12 = 0.5. The decimal length is 10.5 feet.
Steps for Accurate Measurement
- Measure the Length: Use a tape measure to find the longest side of the space. Note down both feet and inches.
- Measure the Width: Measure the perpendicular side (the "short" side) in feet and inches.
- Convert to Decimals: Divide any inch measurements by 12 and add them to the feet measurement.
- Multiply: Multiply the decimal length by the decimal width.
The "Waste Factor" Explained
When purchasing materials like tile, laminate, or sod, pros always recommend adding a "waste factor." This accounts for cuts, mistakes, and odd angles. Standard practice is to add:
- 10%: For standard rectangular rooms.
- 15%: For rooms with many corners or diagonal patterns.
- 20%: For intricate tile patterns or herringbone layouts.
Common Area Conversions
| To Convert From | To | Multiply By |
|---|---|---|
| Square Feet | Square Yards | Divide by 9 |
| Square Feet | Square Meters | 0.0929 |
| Square Inches | Square Feet | Divide by 144 |
| Square Feet | Acres | Divide by 43,560 |
Calculation Example
Suppose you have a deck that is 15 feet 3 inches long and 12 feet wide. You want to buy stain that costs $0.75 per square foot to apply.
- Length: 15 + (3/12) = 15.25 feet.
- Width: 12 feet.
- Total Area: 15.25 × 12 = 183 sq. ft.
- Total Cost: 183 × $0.75 = $137.25.
What if the room isn't a rectangle?
If you have an L-shaped room, the easiest method is to "split" the room into two separate rectangles. Calculate the square footage of each rectangle individually and then add the two sums together for your grand total.